while (during the time)定義：
|While＋過去進行式, （長時間→持續性動詞）||過去簡單式（短時間→瞬間動詞）. 過去進行式（長時間→持續性動詞）.|
|While Tony’s mother was watching TV in the living room,||he woke up（醒來）.|
|While I was doing the laundry,||my husband was cleaning the house.|
|過去簡單式（短時間→瞬間動詞） 過去進行式（長時間→持續性動詞）||while＋過去進行式. （長時間）|
|Tom woke up（醒來）||while his mom was watching TV in the living room.|
|My husband was cleaning the house||while I was doing the laundry|
My friends were speaking loudly in the living room while I was studying in my room.
While I was studying in my room, my friends were speaking loudly in the living room
Mary was singing outside while her brother was dancing inside.
While Mary’s brother was dancing inside, she was singing outside.
While he was cooking in the kitchen, his daughter called him.
His daughter called him while he was cooking in the kitchen.
While 置於句首有「儘管….雖然….」的意思，約等同於Although/ Though
While Jenny has gone to Japan for 5 years, she still can’t speak Japanese well.
While 亦可表達「而…然而….但是…」的意思，約等同於but whereas，可置於句首與句中
Jenny has two son. One of her son is tall while the other is short.
when(at the time)使用時機：
|When I got home,||I took off my shoes|
When I called you, you woke up. 當我打電話給妳時，你醒來。
When I was in junior high school, I used to go to the library every weekend.
When I was child, I lived in Taipei.
I lived in Taipei when I was child.
When Cindy was 20, she got a driver’s license.
Cindy got a driver’s license when she was 20.
When Judy was on a vacation, she got a cold.
Judy got a cold when she was on a vacation.
I met my friends when I arrived at the airport .