根据句意和提示，完成句子。

When you make investigation, ________(最好每次只问一个问题)．

根据句意和提示，完成句子。

He is still in the swimming pool．________(他游了多长时间了)?

根据句意和提示，完成句子。

________(我的家乡发生了巨大变化)since 1980s．

用动词的适当形式填空。

I ________(tell)that the sports meeting may be put off．

用动词的适当形式填空。

The boy fell off the tree and ________(injure)badly．

用动词的适当形式填空。

The detective ________(search)every corner of the room, but it seems that he hasn’t found what he needs．

用动词的适当形式填空。

He died after he ________(save)a drowning child．

用动词的适当形式填空。

No evidence of life ________(discover)on any of the planets so far．

用动词的适当形式填空。

Our group ________(work)on the project since the end of last month．

用动词的适当形式填空。

It’s the third time I ________(be)to Hong Kong．