根据句义，用括号中所给词的适当形式填空。

1. John and Mike ___________ kites near the river now. (fly)

2. It's expensive ____________ to other countries. (travel)

3. Jim _____________ not cook five years ago. (can)

4. The _____________ day of May is his birthday. (twelve)

5. He enjoys _____________ tricks on his friends. (play)

在泵壳与泵轴之间设置密封装置，是为了防止（）或（）。