diff --git a/1000-hours/sounds-of-english/38-fluent.md b/1000-hours/sounds-of-english/38-fluent.md
index 9b56749c..832a34a9 100644
--- a/1000-hours/sounds-of-english/38-fluent.md
+++ b/1000-hours/sounds-of-english/38-fluent.md
@@ -43,6 +43,7 @@
 >   * 轻重
 >   * 缓急
 > * 韵律
+>   * 长短
 >   * 高低
 >   * 起伏
 > * 音素