[练习题]Fill in the blanks with the words given in brackets. Make changes or add something where necessary.My mother(go) to the post office before she went to the supermarket to do her shopping.
正确答案：had gone
题目解析
由题干中的时间状语before she .....可知主句的动作发生在过去的过去，因此应当用过去完成时。因此是had gone。句意：我妈妈在去超市买东西之前去了邮局。
(go) to the post office before she went to the supermarket to do her shopping.