1 . What are you ________ (base) this theory on? （所给单词适当形式填空）

2 . The moment I turned back, the homeless people _____________(beg) for food. （所给单词适当形式填空）

3 . ________ (be) ill, he didn't go to school yesterday. （用所给单词适当形式填空）

4 . An astronomer can determine the __________ (bright) of each star. (所给词的适当形式填空）

5 . Who is __________ (blame) for the accident? (所给词的适当形式填空）

6 . She’s one of those guests who do nothing but ______ (complain). (所给词的适当形式填空）

7 . He learned English by ______ (listen) to the radio. (所给词的适当形式填空）

8 . They were walking so slowly that I began ______ (feel) bored. (所给词的适当形式填空）

9 . Over the years, there ______ (be) a number of different techniques to help designers approach this important point. (所给词的正确形式填空)

10 . It is reported that a new house ______ (build) at present in the disaster area. (所给词的正确形式填空)