用括号里所给词的正确形式填空。
1. The problem is too difficult. It took me half an hour ____________ ( work ) it out.
2. Most people like easy jobs and don't like to do the __________ (pleasant)work.
3.There are some patients _________( wait ) for the doctor.
4. When I walked past,I saw him __________ (play) computer games.
5. Hurry up, the train _______________(leave) in two hours。