diff --git a/avlindex/avlindex.go b/avlindex/avlindex.go
index 67ca76c..7f3cbe7 100644
--- a/avlindex/avlindex.go
+++ b/avlindex/avlindex.go
@@ -115,7 +115,7 @@ func (avl *Tree) removeNode(n *Node) {
 	if ls == 0 && rs == 0 {
 		p := n.parent
 		p.children[getRelationship(n)] = nil
-		avl.fixRemoveHeight(p)
+		avl.fixSizeWithRemove(p)
 		// return n
 		return
 	}
@@ -153,9 +153,9 @@ func (avl *Tree) removeNode(n *Node) {
 
 	// 考虑到刚好替换的节点是 被替换节点的孩子节点的时候, 从自身修复高度
 	if cparent == n {
-		avl.fixRemoveHeight(n)
+		avl.fixSizeWithRemove(n)
 	} else {
-		avl.fixRemoveHeight(cparent)
+		avl.fixSizeWithRemove(cparent)
 	}
 
 	// return cur
@@ -244,9 +244,17 @@ func (avl *Tree) IndexRange(idx1, idx2 int) (result []interface{}, ok bool) { //
 	return nil, false
 }
 
-// func (avl *Tree) GetRange(v1, v2 interface{}) {
-// 	 avl.getArountNode(v1)
-// }
+func (avl *Tree) GetRange(v1, v2 interface{}) {
+	c := avl.comparator(v2, v1)
+	switch c {
+	case 1:
+		var min *Node
+		result := avl.getArountNode(v1)
+		for i := 1; i < 3 && min == nil; i++ {
+			min = result[i]
+		}
+	}
+}
 
 func (avl *Tree) Get(value interface{}) (interface{}, bool) {
 	n, ok := avl.GetNode(value)
@@ -402,38 +410,6 @@ func (avl *Tree) getArountNode(value interface{}) (result [3]*Node) {
 	return
 }
 
-// func (avl *Tree) GetAroundNode(value interface{}) (result [3]*Node) {
-
-// 	if cur, ok := avl.GetNode(value); ok {
-
-// 		var iter *Iterator
-
-// 		iter = NewIterator(cur)
-// 		iter.curPushPrevStack(iter.up)
-// 		iter.up = iter.getPrevUp(iter.up)
-
-// 		if v, ok := iter.tstack.Pop(); ok {
-// 			result[2] = v.(*Node)
-// 			// iter.curPushPrevStack(iter.cur)
-// 		} else {
-// 			result[2] = iter.up
-// 		}
-
-// 		iter = NewIterator(cur)
-// 		iter.curPushNextStack(iter.up)
-// 		iter.up = iter.getNextUp(iter.up)
-
-// 		if v, ok := iter.tstack.Pop(); ok {
-// 			result[0] = v.(*Node)
-// 			// iter.curPushNextStack(iter.cur)
-// 		} else {
-// 			result[0] = iter.up
-// 		}
-
-// 		result[1] = cur
-// 	}
-// 	return
-// }
 func (avl *Tree) GetNode(value interface{}) (*Node, bool) {
 
 	for n := avl.root; n != nil; {
@@ -473,7 +449,7 @@ func (avl *Tree) Put(value interface{}) {
 			fsize := getSize(fixed)
 			if fsize == 3 {
 				lefts, rigths := getChildrenSize(fixed)
-				avl.fix3PutHeight(fixed, lefts, rigths)
+				avl.fix3Size(fixed, lefts, rigths)
 			}
 			return
 		}
@@ -482,7 +458,7 @@ func (avl *Tree) Put(value interface{}) {
 			ls, rs := cur.children[0].size, cur.children[1].size
 			factor := cur.size / 10 // or factor = 1
 			if rs >= ls*2+factor || ls >= rs*2+factor {
-				avl.fixPutHeight(cur, ls, rs)
+				avl.fixSize(cur, ls, rs)
 			}
 		}
 
@@ -698,17 +674,9 @@ func (avl *Tree) lrrotate(cur *Node) {
 	cur.children[r] = mov
 	mov.parent = cur
 
-	// cur.size = 3
-	// cur.children[0].size = 1
-	// cur.children[1].size = 1
-
 	movparent.size = getChildrenSumSize(movparent) + 1
 	mov.size = getChildrenSumSize(mov) + 1
 	cur.size = getChildrenSumSize(cur) + 1
-
-	// mov.height = getMaxChildrenHeight(mov) + 1
-	// movparent.height = getMaxChildrenHeight(movparent) + 1
-	// cur.height = getMaxChildrenHeight(cur) + 1
 }
 
 func (avl *Tree) rlrotate3(cur *Node) {
@@ -742,7 +710,7 @@ func (avl *Tree) rlrotate(cur *Node) {
 	movparent := cur.children[l]
 	mov := movparent.children[r]
 
-	mov.value, cur.value = cur.value, mov.value //交换值达到, 相对位移
+	mov.value, cur.value = cur.value, mov.value //交换值, 达到相对位移
 
 	if mov.children[l] != nil {
 		movparent.children[r] = mov.children[l]
@@ -798,13 +766,9 @@ func (avl *Tree) rrotate(cur *Node) {
 	// 1 right 0 left
 	mov := cur.children[l]
 
-	// lsize, rsize := getChildrenHeight(cur)
-	// movrsize := getSize(mov.children[r])
-
 	mov.value, cur.value = cur.value, mov.value //交换值达到, 相对位移
 
 	//  mov.children[l]不可能为nil
-
 	mov.children[l].parent = cur
 	cur.children[l] = mov.children[l]
 
@@ -825,13 +789,8 @@ func (avl *Tree) rrotate(cur *Node) {
 	// 连接转移后的节点 由于mov只是与cur交换值,parent不变
 	cur.children[r] = mov
 
-	// cur.size = 3
-	// cur.children[0].size = 1
-	// cur.children[1].size = 1
-
 	mov.size = getChildrenSumSize(mov) + 1
 	cur.size = getChildrenSumSize(cur) + 1
-	// cur.height = getMaxChildrenHeight(cur) + 1
 }
 
 func (avl *Tree) lrotate3(cur *Node) {
@@ -860,13 +819,9 @@ func (avl *Tree) lrotate(cur *Node) {
 	// 1 right 0 left
 	mov := cur.children[l]
 
-	// lsize, rsize := getChildrenHeight(cur)
-	// movrsize := getSize(mov.children[r])
-
 	mov.value, cur.value = cur.value, mov.value //交换值达到, 相对位移
 
 	//  mov.children[l]不可能为nil
-
 	mov.children[l].parent = cur
 	cur.children[l] = mov.children[l]
 
@@ -887,10 +842,6 @@ func (avl *Tree) lrotate(cur *Node) {
 	// 连接转移后的节点 由于mov只是与cur交换值,parent不变
 	cur.children[r] = mov
 
-	// cur.size = 3
-	// cur.children[0].size = 1
-	// cur.children[1].size = 1
-
 	mov.size = getChildrenSumSize(mov) + 1
 	cur.size = getChildrenSumSize(cur) + 1
 }
@@ -910,21 +861,21 @@ func getSize(cur *Node) int {
 	return cur.size
 }
 
-func (avl *Tree) fixRemoveHeight(cur *Node) {
+func (avl *Tree) fixSizeWithRemove(cur *Node) {
 	for cur != nil {
 		cur.size--
 		if cur.size > 8 {
-			ls, rs := cur.children[0].size, cur.children[1].size
+			ls, rs := getChildrenSize(cur)
 			factor := cur.size / 10 // or factor = 1
 			if rs >= ls*2+factor || ls >= rs*2+factor {
-				avl.fixPutHeight(cur, ls, rs)
+				avl.fixSize(cur, ls, rs)
 			}
 		}
 		cur = cur.parent
 	}
 }
 
-func (avl *Tree) fix3PutHeight(cur *Node, lefts, rigths int) {
+func (avl *Tree) fix3Size(cur *Node, lefts, rigths int) {
 	if lefts > rigths {
 		l := cur.children[0]
 		llsize, lrsize := getChildrenSize(l)
@@ -944,7 +895,7 @@ func (avl *Tree) fix3PutHeight(cur *Node, lefts, rigths int) {
 	}
 }
 
-func (avl *Tree) fixPutHeight(cur *Node, lefts, rigths int) {
+func (avl *Tree) fixSize(cur *Node, lefts, rigths int) {
 	if lefts > rigths {
 		l := cur.children[0]
 		llsize, lrsize := getChildrenSize(l)
diff --git a/avlindex/avlindex_test.go b/avlindex/avlindex_test.go
index 462f114..913201a 100644
--- a/avlindex/avlindex_test.go
+++ b/avlindex/avlindex_test.go
@@ -67,10 +67,10 @@ func loadTestData() []int {
 func TestIterator(t *testing.T) {
 	// avl := New(utils.IntComparator)
 	// for _, v := range []int{7, 14, 14, 14, 16, 17, 20, 30, 21, 40, 40, 50, 3, 40, 40, 40, 15} {
-	// 	avl.Put(v)
+	// 	tree.Put(v)
 	// }
-	// t.Error(avl.Values())
-	// t.Error(avl.debugString())
+	// t.Error(tree.Values())
+	// t.Error(tree.debugString())
 
 }
 
@@ -206,7 +206,7 @@ func TestGetAround(t *testing.T) {
 func TestPutComparatorRandom(t *testing.T) {
 
 	for n := 0; n < 300000; n++ {
-		avl := New(utils.IntComparator)
+		tree := New(utils.IntComparator)
 		godsavl := avltree.NewWithIntComparator()
 
 		content := ""
@@ -216,17 +216,17 @@ func TestPutComparatorRandom(t *testing.T) {
 			if _, ok := m[v]; !ok {
 				m[v] = v
 				content += spew.Sprint(v) + ","
-				avl.Put(v)
+				tree.Put(v)
 				godsavl.Put(v, v)
 			}
 		}
 
-		s1 := spew.Sprint(avl.Values())
+		s1 := spew.Sprint(tree.Values())
 		s2 := spew.Sprint(godsavl.Values())
 
 		if s1 != s2 {
 			t.Error(godsavl.String())
-			t.Error(avl.debugString())
+			t.Error(tree.debugString())
 			t.Error(content, n)
 			break
 		}
@@ -234,19 +234,19 @@ func TestPutComparatorRandom(t *testing.T) {
 }
 
 func TestGet(t *testing.T) {
-	avl := New(utils.IntComparator)
+	tree := New(utils.IntComparator)
 	for _, v := range []int{2383, 7666, 3055, 39016, 57092, 27897, 36513, 1562, 22574, 23202} {
-		avl.Put(v)
+		tree.Put(v)
 	}
 
 	for _, v := range []int{2383, 7666, 3055, 39016, 57092, 27897, 36513, 1562, 22574, 23202} {
-		v, ok := avl.Get(v)
+		v, ok := tree.Get(v)
 		if !ok {
 			t.Error("the val not found ", v)
 		}
 	}
 
-	if v, ok := avl.Get(10000); ok {
+	if v, ok := tree.Get(10000); ok {
 		t.Error("the val(1000) is not in tree, but is found", v)
 	}
 }
@@ -276,31 +276,31 @@ func TestTravalsal(t *testing.T) {
 func TestRemoveAll(t *testing.T) {
 ALL:
 	for c := 0; c < 5000; c++ {
-		avl := New(utils.IntComparator)
+		tree := New(utils.IntComparator)
 		gods := avltree.NewWithIntComparator()
 		var l []int
 		m := make(map[int]int)
 
-		for i := 0; len(l) < 10; i++ {
+		for i := 0; len(l) < 20; i++ {
 			v := randomdata.Number(0, 100000)
 			if _, ok := m[v]; !ok {
 				m[v] = v
 				l = append(l, v)
-				avl.Put(v)
+				tree.Put(v)
 				gods.Put(v, v)
 			}
 		}
 
-		for i := 0; i < 10; i++ {
+		for i := 0; i < 20; i++ {
 
-			avl.Remove(l[i])
+			tree.Remove(l[i])
 			gods.Remove(l[i])
 
-			s1 := spew.Sprint(avl.Values())
+			s1 := spew.Sprint(tree.Values())
 			s2 := spew.Sprint(gods.Values())
 			if s1 != s2 {
-				t.Error("avl remove error", "avlsize = ", avl.Size())
-				t.Error(avl.root, i, l[i])
+				t.Error("avl remove error", "avlsize = ", tree.Size())
+				t.Error(tree.root, i, l[i])
 				t.Error(s1)
 				t.Error(s2)
 				break ALL
@@ -312,38 +312,35 @@ ALL:
 func TestRemove(t *testing.T) {
 
 ALL:
-	for N := 0; N < 50000; N++ {
-		avl := New(utils.IntComparator)
+	for N := 0; N < 5000; N++ {
+		tree := New(utils.IntComparator)
 		gods := avltree.NewWithIntComparator()
 
 		var l []int
 		m := make(map[int]int)
 
-		for i := 0; len(l) < 10; i++ {
+		for i := 0; len(l) < 20; i++ {
 			v := randomdata.Number(0, 100)
 			if _, ok := m[v]; !ok {
 				l = append(l, v)
 				m[v] = v
-				avl.Put(v)
+				tree.Put(v)
 				gods.Put(v, v)
 			}
 		}
 
-		src1 := avl.String()
+		src1 := tree.String()
 		src2 := gods.String()
 
-		for i := 0; i < 10; i++ {
-			avl.Remove(l[i])
+		for i := 0; i < 20; i++ {
+			tree.Remove(l[i])
 			gods.Remove(l[i])
-			if avl.root != nil && spew.Sprint(gods.Values()) != spew.Sprint(avl.Values()) {
-				// if gods.String() != avl.String() && gods.Size() != 0 && avl.size != 0 {
+			if tree.root != nil && spew.Sprint(gods.Values()) != spew.Sprint(tree.Values()) {
 				t.Error(src1)
 				t.Error(src2)
-				t.Error(avl.debugString())
+				t.Error(tree.debugString())
 				t.Error(gods.String())
 				t.Error(l[i])
-				// t.Error(avl.TraversalDepth(-1))
-				// t.Error(gods.Values())
 				break ALL
 			}
 		}
@@ -570,9 +567,9 @@ func BenchmarkPut(b *testing.B) {
 	execCount := 50
 	b.N = len(l) * execCount
 	for i := 0; i < execCount; i++ {
-		avl := New(utils.IntComparator)
+		tree := New(utils.IntComparator)
 		for _, v := range l {
-			avl.Put(v)
+			tree.Put(v)
 		}
 	}
 }
@@ -587,50 +584,50 @@ func TestPutStable(t *testing.T) {
 			l = append(l, randomdata.Number(3, 69))
 		}
 
-		avl := New(utils.IntComparator)
+		tree := New(utils.IntComparator)
 		for _, v := range l {
-			avl.Put(v)
+			tree.Put(v)
 		}
-		result := avl.getArountNode(60)
+		result := tree.getArountNode(60)
 
-		if result[2] == nil && avl.indexNode(-1) != result[1] {
-			t.Error(avl.debugString())
-			t.Error(avl.Values())
+		if result[2] == nil && tree.indexNode(-1) != result[1] {
+			t.Error(tree.debugString())
+			t.Error(tree.Values())
 			t.Error(result)
 		}
 
-		result = avl.getArountNode(5)
-		if result[0] == nil && avl.indexNode(0) != result[1] {
-			t.Error(avl.debugString())
-			t.Error(avl.Values())
+		result = tree.getArountNode(5)
+		if result[0] == nil && tree.indexNode(0) != result[1] {
+			t.Error(tree.debugString())
+			t.Error(tree.Values())
 			t.Error(result)
 		}
 
-		result = avl.getArountNode(2)
-		if result[2] == nil && avl.indexNode(0) != result[2] {
-			t.Error(avl.debugString())
-			t.Error(avl.Values())
+		result = tree.getArountNode(2)
+		if result[2] == nil && tree.indexNode(0) != result[2] {
+			t.Error(tree.debugString())
+			t.Error(tree.Values())
 			t.Error(result)
 		}
 
-		result = avl.getArountNode(70)
-		if result[0] == nil && avl.indexNode(-1) != result[0] {
-			t.Error(avl.debugString())
-			t.Error(avl.Values())
+		result = tree.getArountNode(70)
+		if result[0] == nil && tree.indexNode(-1) != result[0] {
+			t.Error(tree.debugString())
+			t.Error(tree.Values())
 			t.Error(result)
 		}
 
 	}
 	// for _, v := range []int{10, 0, 9, 5, -11, -10, -1, -5} {
-	// 	t.Error(avl.Index(v))
-	// 	// t.Error(avl.debugString())
+	// 	t.Error(tree.Index(v))
+	// 	// t.Error(tree.debugString())
 	// }
 
-	// avl.RemoveIndex(4)
-	// t.Error(avl.Index(4))
-	// t.Error(avl.Values())
-	// t.Error(avl.debugString())
-	// t.Error(len(l), avl.debugString(), "\n", "-----------") // 3 6(4)
+	// tree.RemoveIndex(4)
+	// t.Error(tree.Index(4))
+	// t.Error(tree.Values())
+	// t.Error(tree.debugString())
+	// t.Error(len(l), tree.debugString(), "\n", "-----------") // 3 6(4)
 
 }