后面动词可以用进行时doing，或者to加动词的形式。
was were本身就是动词，英语中两个动词不能直接放一起，后面动词可以用进行时doing，或者to加动词。还可以是被动语态，后面是动词的过去分词。
扩展
它们是be动词的过去式一、作助动词：现在分词,构成过去进行时态：He was reading；过去分词,构成被动语态：They were defeated.二、作系动词,现在分词、动名词短语作表语： The film was moving.His job was teaching English .过去分词作表语： We were moved.不定式作表语：有to不定式：His work that day was to clean the blackboard.2) 无to 不定式：What he should do is clean the blackboard.
