1 . 当大量的移民到达加利福尼亚但没挖到金子时，他们很有可能非常失望。
________ ________ ________ ________ many immigrants were disappointed when arriving at California and finding no gold then.

2 . It suddenly occurred to him _____ he had left his keys in the office.

3 . It seemed strange that the man who had developed __________ should have lived and died in London. (用适当的词填空)

4 . _______ suddenly occurred to him that he had left his keys in the office.

5 . They say it is impossible to __________(预测) what will happen.

6 . He is likely to win the first prize in the English contest. (句型转换）
_____ _____ _____ _____ he will win the first prize in the English contest.

7 . _______ occurred to him that he had an important conference to attend the next morning.

8 . 大量砍伐树木肯定会扰乱生态平衡。（balance）

9 . It is important to pay your__________（电）bill on time, as late payments may affect your credit.

10 . To help people out of trouble is his lifelong mission.(用it做形式主语改写)
_______________