1/We often shank hands when _____(introduce) to each other 2/after

问题描述:

1/We often shank hands when _____(introduce) to each other 2/after
1、after _______(swim) in the swimming pool
2、/We often shank hands when _____(introduce) to each other 2/after

1.swimming (介词后+doing)
2.introduced(= when we are introduced)
确保正确,可第2题 的when不也是介词么 为什么不用introducing。when可作介词或连词,但本句根据语境,应表示“被介绍时”。本题考查的是过去分词词组作时间状语,表被动,相当于一个状语从句