prep.

(用作时间方面时）

词语辨析：

in, after 

in和after都有“在…以后”的意思

1.

1）after: following in time; later than

Lack of space in Athens is the main reason why the dead are dug up after three years. 雅典的空间不足是埋葬三年后尸体就要被挖出的主要原因。

After travelling for three days I slept for twenty hours at a stretch.连续3天旅行之后，我一连睡了20个小时。

She will go back after three days.

2）in: after (a maximum length of time)；during (a period of time) 

She will go back in three days.

He defeated the champion in three sets. 他三盘击败了冠军。

We did Tokyo in three days. 

我们在东京游览了三天。

2.

after可表示从过去时间算起的一段时间之后,往往与过去时态连用（若接表示时间点的词，也可与将来时态连用）; in则表示从现在时间算起推移到将来的一段时间之后,一般与将来时态连用。