用括号中的单词填空.I have a large _____ of stamps.(collect)

问题描述:

用括号中的单词填空.I have a large _____ of stamps.(collect)
用括号中的单词填空.
I have a large _____ of stamps.(collect)
答案是collection ,为什么不加s

这儿的collection是单数名词,前面有a修饰.