present(now) future past 现在完成时 ( present perfect tense) do my homework Mother: John, clean your teeth please. John: Mum, I have have already already ( (已经 已经 ) cleaned ) cleaned them. comb your hair - have combed it wash your hands - have washed them study for English test - have studied for it tell me the truth -have told you everything visit your grandpa - have visited him listen to the English tape - have listened to it Mother: John, clean your teeth please. John: Mum, I have already cleaned