现在be /do
过去were/was /did
将来be doing /will do
过去将来would/should do
现在完成has/have done
过去完成had done
将来完成will have done
过去将来完成should have done
现在进行be doing
过去进行were/was doing
将来进行will/shall be doing
过去将来进行would/should be doing
现在完成进行have been doing
过去完成进行had been doing
将来完成进行will/shall have been doing
过去将来完成进行would /should have been doing