1. 选词填空

die from, insist on, find out, draw a conclusion, graduate from, get stuck, lead to

1. （1） "The error, if not checked, could an overall disaster," he said.
3. （2） If you ever , ask around for help until you are able to complete a given task.
5. （3） Up to half of all smokers will a tobacco-related disease.
7. （4） They need to interview some people and if they like their jobs.
9. （5） USA, Qian Xuesen managed to come back home to serve our motherland.
11. （6） Ma Yun retiring and trying to have a change of his life last year.
13. （7） You had better keep on trying if you find it difficult to .