动词原形-动词单三-动词现在分词-动词过去式-动词过去分词
eat/eats/eating/ate/eaten
watch/watches/watching/watched/watched
am/is/are-was/were-been
现在完成时公式:
have/has + 动词过去分词
have dinner:
I have had dinner.
I have eaten an apple.
have been to + 地方 到过...
I have been to Beijing.
I have not been to Beijing.
Have you been to Beijing?
Yes, I have. No, I haven’t.
all the time 一直
already/just/never
just like...