The book had been sold out when I got to the bookstore yesterday afernoon.

问题描述:

The book had been sold out when I got to the bookstore yesterday afernoon.
The book【 had been sold out】 when I got to the bookstore yesterday afernoon.为什么不填has been sold out?因为从句中的got 可连接词是when而不是before啊?

这是过去完成时,而has been sold out是现在完成时,before既可以做介词,又可以做连词,意思是"在^之前".后面接句子时,是连词,如:I had taught in that school before I moved here.before后面接单词或者短语时,是介词...