we are going to stay in ShangHai for_____ A a or two year B a year or two

问题描述:

we are going to stay in ShangHai for_____ A a or two year B a year or two
A为何不可?

选B
a year or two 表示一两年的意思
例句:why do couples only last for about a year or two?
翻译:为什么婚姻生活只能维持一两年时间?
对于A 表达错误.