1、The joke served as a lead-in to a discussion of more serious matters
這個笑話是為了引入討論更嚴肅的問題

2、Tell a story to ss. Lead-in the new sentences:This is an apple. /That's a pear.
通過講故事，引入新句型，并在講的過程中適時復習水果名稱。

3、The joke served as a lead-in to a discussion of more serious matters.
這個笑話是為了引入討論更嚴肅的問題

4、Lead-in CAPP system based on SolidWorks feature model
基于Solid Works特征模型的導入式CAPP系統(tǒng)

lead-in翻譯