- while 指一段時間。
- 用法一：While S ＋ was ／ were ＋ V-ing..., S ＋ V-ed... = S ＋ V-ed... while S ＋ was ／ were ＋ V-ing...
- 如：While we were having dinner, Grandpa came to visit us. = Grandpa came to visit us while we were having dinner.
- （我們正在吃晚飯時，爺爺來拜訪我們。）
- 用法二：While S ＋ was ／ were ＋ V-ing..., S ＋ was ／ were ＋ V-ing... = S ＋ was ／ were ＋ V-ing... while S ＋ was ／ were ＋ V-ing...
- 如：While I was preparing for my test last night, my neighbor was having a party. = My neighbor was having a party while I was preparing for my test last night. （我昨晚在準備考試的同時，我的鄰居在開派對。）