for the weekend與for a week的區別

for the weekend這個短語不常見，通常情況下介詞for後面應該加上一段時間，因此for a week才是常用的短語。

for a week表達的意思是“（動作持續了）一段時間”，如：They're going to stay in Shanghai for a week. 他們打算在上海待一星期。They have been in Shanghai for a week