21. We spent a week in Paris and had a great time going up______ Eiffel Tower, and taking_______ boat trip along the Seine
A. a: a B. the: a C. the: the D. (不填)：（不填）
22 I have an important meeting_______ in an hour, but I can’t find anywhere to park my car.
A. to attend B. be attended C. attending D. attend
23._______ his experiment, the young man didn’t notice what was happening outside.
A. Involving in B. Involved in C. To be involved D. Being involved in
24. The living room is clean and tidy, with a dining table already_______ for a meal to be cooked.
A. laid B. laying C. to lay D. being laid