题目：
The place __ the bridge is supposed to be built should be ____the cross-river traffic is the heaviest .
A．which; where
B．at which ;which
C．at which ;where
D．which ;in which
答案：
C.
“he bridge is supposed to be built”是定语从句，修饰名词place。“he cross-river traffic is the heaviest”组在句中做表语，表语从句引导词中没有in which，两空结合
