书名：多益题库解析
页数：32
题目：148
疑问：
If you unable to retrieve the truck yourself, you may send a representative who
must present a valid identification and a letter _____ that you permit
him or her to claim the vehicle on your behalf
A indicates B indicating C indicated D indication
大家好，我想请问为什么不能选A要选B?
选B是作为形容辞修饰letter
但个人认为可以选A的理由是由于and对等连接词的关系，将you may......,a letter....
视为两个子句，a letter的子句缺少动词，故选A
不知道哪里的观念有误，还请大家解惑
谢谢