前天下午我们在图书馆前遇到李丽 用英语咋说

1.His mother mustn't be at the butcher's shop today.
2.Mary didn't come to school on the afternoon of the day before yesterday.She could have gone to Paris.
Cici,who is packing her suitcase,must be going to Shanghai tomorrow evening.
3.This is the key __to__(介词)　the door.
4.There isn't any lemonae in the cup.(否定句)

下面提供一些 in 和 on 的对于时间和日期的习惯用法：
IN
Use 'in' months and years and periods of time:
in January
in 1978
in the twenties
Use 'in' a period of time in the future:
in a few weeks
in a couple of days
AT
Use 'at' with precise time:
at six o'clock
at 10.30
at two p.m.
ON
Use 'on' with days of the week:
on Monday
on Fridays
Use 'on' with specific calendar days:
on Christmas day
on October 22nd
注意：
我们说
in the morning / afternoon / evening
但我们说
on the morning / afternoon / evening of
而且,我们说
at night
就你的提问：
前天早晨 / 前天下午
the morning / afternoon of the day before yesterday 前面加 in 或 on 皆可,
但本人的习惯是用 on
前天晚上9点半的时候 / 后天早上9点半的时候
用 on 和 in 都可以：
Your flight departed at half past nine (on/in) the evening of the day before yesterday
The flight took place (on/in) the evening of the day before yesterday
但两者语境不同,
用 on 来表示“在那一天” ,比如 the day before yesterday 前天
用 in 来表示“时间”,比如“傍晚时间”,during the hours of the evening,即 6点整到 10 点整左右.
说实话,很多英语母语者对这个英语的诡异也很纠结,
就是这个原因,一般人忽略 in 和 on 介词,
干脆只用名词 morning ,afternoon 等等：
Your flight departed at half past nine the evening of the day before yesterday
The flight took place the evening of the day before yesterday

今天下午 this afternoon
昨天下午 yesterday afternoon
前天下午 the afternoon of the day before yesterday

on the morning/afternoon of the day before yesterday
on the morning/afternoon of the day after tomorrow
on the evening of.the day before yesterday/ on the evening of the day after tomorrow
one morning three days ago/ one morning in three days
one night five days ago/one night in five days
at half past nine in the evening the day before yesterday/ at ten in the morning the day after tomorrow