Question

At a construction site in our city the workers have uncovered an ancient wall that_______ to keep the enemy out of the city, but it requires further evidence.

A. might have functioned                              B. would have functioned

C. must have functioned                               D. should have functioned

Answer

A

【解析】考查虚拟语气。might have done 意为“过去可能是做什么的”，是对过去肯定的猜测。句意为：在市里的一处工地上，工人们挖出了一道以前可能是用来御敌的城墙，但这还有待进一步验证。根据句意选A。