21 關(guān)系副詞when的用法　Track 021

（1）先行詞指時間
when引導限制性和非限制性定語從句，其先行詞須是表示時間的名詞，如day，year，time等。when可用“時間介詞+ which”來替換。
例句
a. I’ll never forget the day when I met you.
b. I’ll never forget the day on which I met you.
c. April Fool’s Day is that special day of the year when you should play a joke on someone! Children’s favorites are to put salt in the sugar bowl for Dad’s morning coffee or put chalk on a desk chair at school so the teacher gets a white backside! But remember, if you play a joke after 12 noon, YOU are the April Fool!
d. We will put off the outing until next week, when we won’t be so busy.
e. March 10, 1876 was the day when（= on which） the first complete sentence was sent over a telephone.
f.The day may soon come when we don’t bother to go to office but just work at home.
（2）關(guān)系副詞when在從句中作時間狀語
注意：表示時間的先行名詞，若其定語從句不是缺狀語，而是缺主語或賓語，關(guān)系詞要用which或that。因為用when來引導定語從句的前提條件是：when在其所引導的定語從句中作時間狀語。
例句
a. The day, which began brightly, ended with a violent storm.
那天開始的時候還是晴空萬里，后來卻下起了暴風雨。（which作主語）
b. I’ll never forget the time which I spent on campus.（which作spent的賓語）
c. I’ll never forget the day when we first met in the park. (when作時間狀語，修飾met)