現(xiàn)在進行時: 主語+am/is/are doing
e.g We are cleaning the room now.
過去進行時: was/were doing
e.g We were cheaning the room at 5:00 yesterday afternoon.
現(xiàn)在完成時: have/has done
We have cleaned the room already.
過去完成時: had done
e.g We had cleaned the room before he arrived.
一般將來時: will do/
e.g We will clean the room tomorrow.
過去將來時: was/were to /would do
e.g He said he would clean the room next.