Our headmaster went to pay a two-week visit to our sister school in Japan and he will be back in___为什么用a day or two不用a day or two days
问题描述：
Our headmaster went to pay a two-week visit to our sister school in Japan and he will be back in___
为什么用a day or two不用a day or two days
答
a day or two 一两天, 习惯说法而已, 记住就行了.
答
这个就是英语的语言习惯，省略最后的days。这个没有原因好讲啊。
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答
a day or two
=one or two days 一两天