'I _have explained 完成時(shí)表示一段時(shí)間內(nèi)重復(fù)做某事_(explain)this to you several times already,'said the teacher.'I hope you_understand 虛擬,用原形_(understand)it now.'Then he loooked at a little boy at the back of the class.'Are you listening 表示一個(gè)狀態(tài),所以用現(xiàn)在進(jìn)行時(shí)_(listen),Jones?'he asked.'Here is a simple problem:"Sally has worked后面有for引導(dǎo)的時(shí)間狀語(yǔ),所以要用完成時(shí)表示動(dòng)作一直持續(xù)(work)in an office for thirty-four weeks.In that time,she_earned_(earn)300yuan a week.How much_has_she_earned后面是“到目前為止”也要用完成時(shí)_(earn)so far.
'Please,sir,'Jones answered,'I can only answer your first question.I _am not listening表示狀態(tài),跟前面一樣_(not listen).'