24．You'd better write to her at once. You'd better

　　____ ____ to her at once.

23．Let's get there by taxi.

　Let's ____ ____ there by taxi.

22．Call me at six tomorrow evening.

　　____ call me at six tomorrow evening.

21．She does morning exercises every day.

　She ____ ____ morning exercises every day.

20．I bought some books last week.

　I ____ ____ ____ __books last week.

19．I can sing the Japanese song very well.

　I ____ sing the Japanese song very well.

18．He has been to America twice, too.

　He ____ been to America twice, ____.

17．They are having a good time in the park.

　They ____ having a good time in the park.

16．There will be an English film this week.

　There ____ be an English film this week.

15．We'd better go there on foot.

　We'd better ____ ____ there on foot.