1£®The police________(determine) to bring back the missing boy when his family ________(have) almost given up all hope.

2£®He is one of the old scientists who________(care) little about personal income and fame.

3£®Professor James will give us a lecture on the Western culture£¬but when and where________(not decide) yet.

4£®The father as well as his three children ________(go) skating on the frozen river every Sunday afternoon in winter.

5£®The police ________(search) the street for the murderer at present.

6£®One third of the students ________(invite) to attend his birthday party yesterday.

7£®Our clothing ________(protect) us from the cold.

8£®As I have a meeting at four£¬ten minutes________(be) all that I can spare to talk with you.

9£®Last week John with his classmates________(busy) in preparing for the exam.

10£®In my opinion£¬the rich________(be) not always happier than the poor£¬for money doesn't mean everything.