Tom has been studying the electronics since he left school two years ago 为啥用 has been studying给我再细讲讲 现在完成时

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Tom has been studying the electronics since he left school two years ago 为啥用 has been studying给我再细讲讲 现在完成时

Tom has been studying the electronics since he left school two years ago 为啥用 has been studying给我再细讲讲 现在完成时
Tom has been studying the electronics since he left school two years ago 为啥用 has been studying
给我再细讲讲 现在完成时

Tom has been studying the electronics since he left school two years ago 为啥用 has been studying给我再细讲讲 现在完成时
用 has been studying,是现在完成进行时,表示动作从过去某一时间开始进行,一直延续到现在,可能还要继续下去,通常与表示一段时间的状语连用,如：for hours,since 1990,since 从句等.这句话的意思是说 Tom自从两年前就一直在学电子学,一直持续到现在,还有可能持续下去.而现在完成时表示过去动作对现在的影响,并且表示这一动作已完成或还可能继续下去,总之对现在已经造成影响了.

表示已经学习了一段时间……

汤姆自从两年前离开学校就一直在学电子
以下是百度百科来的，讲的蛮好
现在完成时（Present perfect）
（1）现在完成时用来表示现在之前已发生过或完成的动作或状态,但其结果却和现在有联系,也就是说,动作或状态发生在过去但它的影响现在还存在，也就是说，动作发生在过去，而对现在造成的影响和结果. 　　
　I have spent all of my money...

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汤姆自从两年前离开学校就一直在学电子
以下是百度百科来的，讲的蛮好
现在完成时（Present perfect）
（1）现在完成时用来表示现在之前已发生过或完成的动作或状态,但其结果却和现在有联系,也就是说,动作或状态发生在过去但它的影响现在还存在，也就是说，动作发生在过去，而对现在造成的影响和结果. 　　
　I have spent all of my money.(现在我没有钱花了.) 　
　Jane has laid the table.(简已经摆好了桌子) 　
　Michael has been ill.(现在仍然很虚弱) 　　
He has returned from abroad. (现在已在此地)
（2）现在完成时可以用来表示发生在过去某一时刻的,持续到现在的动作（用行为动词表示）或状态（be动词表示）常与for（+时间段）,since（+时间点或过去时的句子）连用. 　　　①for+时段 为…时间 　　②since+过去一个时间点（译为：自从……以来） 　　③since+时段+ago 　　④since+从句（过去时） 　　●⑤It is+时段+since+从句（过去时） 　　Mary has been ill for three days. 　　I have lived here since 1998. 　　●注：瞬间动词（buy,die,join,lose……）不能直接与for since 连用。要改变动词 　　come/arrive/reach/get to-----be in 　　go out----be out 　　finish----be over 　　open----be open 　　die----be dead 　　Buy---have 　　Fall ill---be ill 　　Come back---be back 　　Put on ---be on/wear 　　Worry---be worried 　　Catch a cold---have a cold

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all the students except tom has been abroad改错 Tom has been on the island since two years.(改错) it is 3 years since Tom has been abroad tom didnt smoke has been two years有语法错误吗 Tom has been a________(成员) of the volleyball team Tom ________France .He _____Paris for three weeks.a.has been to :has been tob.has gone to :has been inc.has been to:has been ind..has gone to; has been to并说明原因 Tom got sick last May and has been in bed since then.为什么has been 而不是had been the room has been cleaned by tom 对tom提问____ ____the room____ cleaned ____ Tom’s grandfather （has been dead） for five years为什么不是has been died? 告诉我原因谢谢. 这句话有几个助动词The work has been done by tom .has 和 been哪个是助动词 为啥 Tom has been in China for three years.(改为同义句)1.Tom has been in China ( ) three years( ).2.Three year ( ) ( ) ( ) Tom cane to China.3.Tom ( ) ( ) China three years ( ).4.It is ( ) ( ) ( ) Tom came to China. Tom has been in China for three years.(改为同义句)1.Tom has been in China ( ) three years( ).2.Three year ( ) ( ) ( ) Tom cane to China.3.Tom ( ) ( ) China three years ( ).4.It is ( ) ( ) ( ) Tom came to China. Tom ( ) the Islands of Hawaii.He surfs three times a day there .A has gone to B has gone on C has been for D has been I have been to the Water World .Tom has been there,too句行转换句型转换1.I have been to the Water World .Tom has been there too_______Tom_______I have been to the Water World -I have been to hongkong.-____.he went there last summer A.so has tom B.so did tom C.so tom has D. has been Tom has been ill for three days.改为否定句,一般疑问句和被动语态 Tom said he has never been to Hong Kong.反义疑问句