问题
选择题
Various efforts over the centuries _________ to predict earthquakes to reduce the damage.
A．are being made
B．have been made
C．were made
D．were being made
答案
B
题目分析：句意：几个世纪以来，已经做了各种努力来预测地震，减少损失。make efforts 做出努力，变被动形式。故选B。
考点: 考查动词时态和语态的用法。