特点
这种时态很少用在否定句中,而多以过去完成时代替:
He had not practised English for many years.(普通说法)
He had not been practising English for many years.(少见)
这种时态还可用在said,supposed等引起的间接引语中,代替现在完成进行时:
He said,“I have been speaking to John.”= He said that he had been speaking to John.
He thought,“She was watching me when I passed.”= He thought that she had been watching him when he had passed.
过去完成进行时经常与现在完成进行时混淆。
现在完成进行时 (The present perfect progressive) 由 have/has been +-ing 分词构成;
过去完成进行时( The past perfect progressive tenses )由 had been +-ing 分词构成.
现在/过去完成进行时的用法:
A. 在某段时间内一直进行的动作用现在完成进行时来强调动作在某段时间里的持续性.动作通常有"现在"的结果,要根据上下文来确定到"现在"为止,动作是否还在继续进行.同样,过去完成进行时表示在过去更早时间内进行的动作,并对过去某一时刻产生结果。
B.表示重复动作的现在/过去完成进行时
我们也可以用完成进行时形式来表示现在或过去经常重复的动作
注意:过去完成进行时和过去完成时类似,需要有过去这一时间点。