1 . can
bottom底部can可以ulterior隐秘的
2 . could
few a few 少数could 可以for 为
3 . may
...arn(学习)--learnt,leave(离开)--left,let(让)--let,lie(躺,平放)--lay,make(使得,做)--made,may(可以)--might,must(必须)--must,ride(骑)--rode,ring(鸣铃)--rang,run(跑)--ran,say(说)--sai.
4 . will
Bring a player into an empty stadium and he will score nine out of ten ., 带一名球员到空旷的球场他可以点球十罚九中.