21、It took us quite a long time to get there. It was _________ journey.
A. three-hour B. a three hour C. a three-hour D. three hours
22、People, especially teens, think it _____ great fun to surf on _____ Internet.
A. a; the B. a; 不填 C. 不填; the D. 不填；不填
23、-----What did the teacher say just now?
-----Sorry. I didn’t catch it. I ___________ something else.
A. think about B. will think about C. was thinking about D. thought about
