问题
选择题
—People find it hard to get across the river．
—I think at least two bridges over it．
A．need
B．are needing
C．will need
D．should be needed
答案
答案：D
本题的含义是在河上至少需要两座桥，本题桥在从句作主语，是动作的承受者，故被动结构，结构为be+过去分词，need的过去分词是needed，故选D。