21. ________ back in his chair, the man began to tell us his adventures in the forests.
A
Sit
B
Sitting
C
To sit
D
Sat
23. ______ more about our university courses, write to this address.
30. A notice will be put up_____ information about the closing dates for entering exams.
32. ––Do you mind if I smoke here?
––I suggest you go to the separate room ______ for smokers.
句意：坐回到自己的座位，这个人开始讲述他在森林中的冒险。此处考查现在分词作时间状语。故选B。
现在分词
判断结构
抓不住要点
容易