问was a后加什么词

接名词单数

如：

It was a desk.

There was an apple on the tree yesterday.

1. 现在分词,构成过去进行时态：He was reading.2.过去分词,构成被动语态：They were defeated.二、作系动词3.现在分词、动名词短语作表语：The film was moving.His job was teaching English .4.过去分词作表语：We were moved.5.不定式作表语：1）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.