When Before After的用法
When Before After的用法
Before After When當連接詞的用法
1. 在現在式、過去式，主要句子和從屬子句的時態須一致。
He goes to bed after he takes a shower. (他洗澡後上床睡覺 )
Yesterday I walked to school after I finished my breakfast.（吃完早餐後，我去上學）
I do my homework before I eat dinner.吃晚餐前，我做功課
I read some books before I went to bed last night.我昨晚睡前讀了一些書
When I was twelve , I joined the army. 當我12歲時，我加入軍隊
When mom told me the fact, I felt surprised.當媽媽告訴我事實，我感到驚訝
2. 如果主要子句用未來式，Before After When的從屬子句動詞必須用現在式代替未來式。
After he comes back tomorrow, we will leave here.
明天他回來後，我們將會離開這裏
Before Mary goes to USA next Sunday, we will have a goodbye party for her.在瑪麗下星期日去美國前，我們將舉辦一個歡送會。
When he arrives here tomorrow , I will call him.
當他明日抵達這裡，我會打電話給他
3. Before + 後發生的事情
After + 先發生的事情
He takes a shower before he goes to bed.
( 他上床睡覺之前，他洗澡了 )
He goes to bed after he takes a shower.
( 他洗澡之後，他上床睡覺 )
Before和After當作介系詞用法
1. Before和After後面接名詞(n)
He studies very hard before the test this time. (這次考試之前，他非常認真唸書)
He bought many snacks before the field trip.遠足前，他買了很多零嘴
I felt scared after the large earthquake.大地震過後，我感到害怕
I have learned a lot of things after the trip to Africa.在非洲之旅過後，我學到很多東西
2. When,Before和After後面接動名詞(Ving)
Before和After所引導從屬子句，如果主詞與主要子句相同時，去除從屬子句的主詞並將動詞改為動名詞。
After she ate dinner, she watched TV.
= After eating dinner, she watched TV.吃完晚餐後，她看電視
After she played the violin, she played basketball.
= After playing the violin, she played basketball.彈完小提琴後，她打籃球
Before she took the tests, she studied hard.
= Before taking the tests, she studied hard.參加考試前，她用功唸書
Before you cook the vegetables, you must wash them.
= Before cooking the vegetables, you must wash them.在烹煮蔬菜前，你必須先洗一洗
When I watch TV , I usually have some popcorn.
= When watching TV, I usually have some popcorn.當看電視時，我常常吃爆米花
When I do the sports, I like to wear sneakers.
= When doing the sports, I like to wear sneakers.當運動時，我喜歡穿運動鞋
