回上一層第四部 第十課 --- 請重複跟讀，直到可以於聲音檔的留空之間唸完整句為止；熟練之後您必將可以 "脫口而出" 地說出標準的美式英語
- every so often
- Every so often I like to go sailing with my friends.
- fall behind
- Dorothy fell behind in class, but she didn't give up.
- During the tour, I fell behind and couldn't catch up.
- fall flat
- Your best design fell flat in the contest.
- fall off
- The economy has been falling off for last five years.
- The revenue from the football stadium has fallen off over the years.
