1 . 选择填空：while, but, however
1. I would like to help you. _________, I don’t know how to operate the computer.
2. They rushed to the airport, _________ they were too late.
3. Their country has plenty of oil, _________ ours has none.

2 . 用方框中所给短语的适当形式填空，每个短语只用一次。

once and for all             in charge of          deep down       come down with     be rich in

1. He was placed ________ this department.
2. What if I ________ a strange disease?
3. Let’s solve this question ________ !
4. He seems confident but ________ he lacks confidence.
5. Apples ________ vitamins.