10.Helen ___ her key in the office so she had to wait until her husband___ home.

题目

10.Helen ___ her key in the office so she had to wait until her husband___ home.
A.has left,comes
B.left,had come
C.had left,came
D.had left,would come详细解析为什么选C

答案

c,
she had to wait 这句可以看出时态是过去,until 后也用一般过去时.排除D.把钥匙落在办公室是在等她丈夫之前 ,时态应该是过去的过去,即过去完成时,所以第一空先可以排除A.B.故选C.