Mary has been playing the guitar for two hours.(改为一般疑问句) ---

Mary has been playing the guitar for two hours.(改为一般疑问句) --- They have been practicing the guitar for two hours.(改为同义句) 将he has been playing comquter games for two hours改为同义句 Mary can play the guitar.(改为一般疑问句） Lisa has been playing the violin for two years 改为否定句 把Mary has two brothers改为一般疑问句, 1.---“ _______ has Mary been playing the piano?”---“ For thr The meeting has been off for two hours.It______since_______. The dog has been _(die)for two hours. Mary likes playing the piano.改为一般疑问句,并回答 The train has been in the station for two hours.She has been （1）she likes playing the guitar?改为一般疑问句,并作肯定回答