助动词的强调句有固定的时态吗?

助动词的强调句有固定的时态吗?在书上看到只能和一般现在时和过去时的肯定句连用,可是在they do have increased political power,就是现在完成时了,还有he did not think l had really done the work,but l did.这也不是肯定句吧,错了，是这个he did not think l had really done the work,but l had!这不就是强调句吗