diff --git a/GPT_SoVITS/text/tone_sandhi.py b/GPT_SoVITS/text/tone_sandhi.py
index 5ad292f1..e9a279c6 100644
--- a/GPT_SoVITS/text/tone_sandhi.py
+++ b/GPT_SoVITS/text/tone_sandhi.py
@@ -654,18 +654,19 @@ class ToneSandhi:
         # function 1
         while i < len(seg):
             word, pos = seg[i]
+            merged = False
             if (
                 i - 1 >= 0
                 and word == "一"
                 and i + 1 < len(seg)
-                and seg[i - 1][0] == seg[i + 1][0]
-                and seg[i - 1][1] == "v"
-                and seg[i + 1][1] == "v"
             ):
-                merged = seg[i - 1][0] + "一" + seg[i + 1][0]
-                new_seg[-1] = [merged, seg[i - 1][1]]
-                i += 2
-            else:
+                last = new_seg[-1] if new_seg else seg[i - 1]
+                if last[0] == seg[i + 1][0] and last[1] == "v" and seg[i + 1][1] == "v":
+                    combined = last[0] + "一" + seg[i + 1][0]
+                    new_seg[-1] = [combined, last[1]]
+                    i += 2
+                    merged = True
+            if not merged:
                 new_seg.append([word, pos])
                 i += 1
         seg = new_seg