问题描述：
（where ）the bridge is supposed to be built should be a place ( at which ) the cross river traffic is the heaviest A A where , at which B at which, which C at which, where D which, in which The place( )the bidge is supposed to bebuilt should be( )the cross river traffic is the heaviest C 老师你详细讲讲吧，我真不明白
问题解答：
我来补答
解题思路： 复合
解题过程：
1.______ the bridge is supposed to built should be a place _____ the cross river traffic is the heaviest.
A. Where, at which B. At which, which C. At which, where D. Which, in which
答：第一个空是主语从句。而at which是不能引导主语从句的，故B和C错误；再该主语从句中不缺少主语、宾语、表语，故不能用which。
第二个空是定语从句。该定语从句不缺少主语、宾语、表语，故需要用关系副词，或“介词+关系代词”的形式。故A正确。
2. The place _____ the bridge is supposed to be built should be _____ the cross river traffic is the heaviest.
A. Where, at which B. At which, which C. At which, where D. Which, in which
答：第一个空是定语从句。该定语从句不缺少主语、宾语、表语，故需要用关系副词，或“介词+关系代词”的形式。因而D错误。
第二个空是表语从句。而at which是不能引导表语从句的，故A和D错误；再该主语从句中不缺少主语、宾语、表语，故不能用which，因而B错误。所以C是正确的。
明白了么？如果有疑问，可以给我再留言！
最终答案：略
