6 他一定知道计算机出了什么毛病,因为他对计算机懂得很多。(what's wrong with, know a lot about)
Reference
1 We can go to school by bike or on foot.
2 Her writing is both simple and interesting.
3 I think we should get up as early as possible.
4 We have to speak English both in and out of class.
5 Our teacher is very strict with us. We can learn a lot from him.
6 He must know what is wrong with the computer, because he knows a lot about computer.