27.[1996全国] ________ in thought, he almost ran into the car in front of him.

26.[1995全国]—I'll be away on a business trip. Would you mind looking after my cat?

—Not at all. ________.

24.[1995全国]—You were brave enough to raise objections at the meeting.

—Well, now I regret ________ that.

23.[1995全国] We agreed ________ here but so far she hasn't turned up yet.

21.[2001全国] ________ such heavy pollution already, it may now be too late to clean up the river.

A. Having suffered　　　　　　　　　　    B. Suffering　　  

C. To suffer　　　　　　　　　　    D. Suffered

20.He buried the money, without anyone ________ where it was.

19.The book, ________ as a surprise for his sister, was lost in the mail.

18.They know her very well. They had seen her ________ up from childhood.

17.—What made Sam so angry?

—________ in the rain for quite a long time.

16.He hurried to the bus stop, only ________ that the bus had left.