1. 時間類
1.) when/as

i. Leonard was nine when his father died.
ii. As time passed, things seemed to get worse.


2.) Whenever

i. every time that a particular thing happens
1. Whenever I hear that tune, it makes me think of you.
ii. at any time:
1. Come and visit me whenever you want.



3.) While

i. during the time that something is happening
1. While she was asleep, thieves broke in and stole her handbag.
ii. used to emphasize the difference between two situations, activities etc:
1. Schools in the north tend to be better equipped, while those in the south are relatively poor.


4.) since

i. from a particular time or event in the past until the present, or in that period of time:
1. It was exactly five years since her father had died.
ii. Use since to say that something started at a point in time in the past, and is still continuing
iii. Use for when you state the length of time that something has been happening
iv. During and over are used when you state the period of time in which something happens or changes


5.) Till（介）/until（連）

i. if something happens until a particular time, it continues and then stops at that time:
1. Until recently, Anna worked as a teacher in Japan.


6.) not…until

i. used to emphasize that something does not happen before a certain point in time or before something else has happened:
1. It was not until 1972 that the war finally came to an end.


7.) by the time

i. By the time they get here, we'll have finished the work.



8.) hardly/scarcely/barely…when/before=no sooner had/did... than

i. Rarely and seldom both mean 'not often'. Seldom is more formal or literary
ii. Hardly and scarcely both mean 'almost not' or 'only just'. For example, if you hardly had time to do something, you almost did not have time. Scarcely is more formal or literary
iii. only a moment ago [= hardly, barely]:
1. He had scarcely sat down when there was a knock at the door.
iv. no sooner had/did ... than used to say that something happened almost immediately after something else:
1. No sooner had he sat down than the phone rang.


9.) as soon as

i. as soon as ：immediately after something happens, without delay:
1. As soon as she entered the room, she knew there was something wrong.