新概念3第一课有个句子不太明白Theexpertswerenowfullyconvincedthattheanimalwasapuma,butwherehaditcomefrom?这里为什么要用过去完成时还有come难道不要变成came?Asnopumashadbeenreportedmissingfroman

Question

新概念3第一课有个句子不太明白
The experts were now fully convinced that the animal was a puma,but where had it come from?这里为什么要用过去完成时 还有 come难道不要变成came?
As no pumas had been reported missing from any zoo in the country,this one must have been in the possession of a private collector and somehow managed to escape.这里为什么用过去完成时

Answer 1

首先,过去完成时态的构成是had+过去分词,come 是不规则动词,过去式came,过去分词come过去完成时用于描述,过去某个时间之前发生的事件或所做的动作.在同一个句子里,比如复合句里,说两件过去发生的事件,发生更早的,可...