Planes have tried to catch them,but they always failed.为什么不能用fail?前后的时态怎么确定?

Planes have tried to catch them,but they always failed.为什么不能用fail?前后的时态怎么确定? I have just tried to ring you... 翻译成中文 they tried various kinds of material to make planes 、 finally making their dream come t 7.All possible means __________ to save the hero.A.has tried B.have tried C.has been tried D.have been tried 造句:to,have,ever,up,him,tried,cheer,you Have you ever tried () to a foreigner in English? you might have tried to be a little quietre last night 能否改成 you should have tried to be a . Have they tried to send information to us?不定式 tried to 在这里做什么（例：谓语?……）Have they tried to send information to us?不定式 tried to 在这里做什么（例：谓语?……） Every possible means _______ to save the wounded hero up to now.Every possible means _______ to save the wounded hero up to now.A.have tried B.has tried C.have been tried D.has been tried Have you ever ___some vegetables on your roof?It's really interesting.tried to grow/tried growing -Have you ( )him to give up smoking?_No.I( ),but he wouldn't listen.A.persuaded:triedB.tried:persuaded C.tried:tried D.persuaded;persuaded every possible meanssafe to drink.A.is triedB.has been tried C.have been tried D.are tried 改选哪一个为什么? All possible means____to save the wounded soldier A have been tried B is to be tried C has been tried Dare trying Scientists have tried to set fire to underground coal to speed up the fires. If you have one chance to do something you have never tried,what will it be? facing the economic depression ,every possible means( )this year to save the company from going bankrupt.A.has been tried B.has tried C.have been tried D.have tried这里为什么选c I tried to call They have tried to limit such imports in order to protect their members' jobs!句中tried to是什么成份啊?