전치사의 생략

1. for가 기간을 나타낼 때 

We have lived here (for) twelve years. 
(For) How long have you owned this house? 

2. on을 요일이나 morning, afternoon, night 등 시간을 나타내는 명사 앞에 사용 할 때 

He went surfing (on) Saturday. 
I bought these shoes (on) Friday night. 

3. 때를 나타내는 in, on, for를 이끌어 내려고 하는 질문에 대한 답에서 

How long have you lived here?  (For) two years. 
When do you wake up? (At) 7 a.m. 

4. 시간, 거리, 방법, 정도, 양태 등을 나타내는 명사 앞에서

(At) What time does your school begin? 
It lasted (for) three hours. 
Do it (in) this way. 

5. 때를 나타내는 명사구가 서수나 late, next, this, that 등 지시 한정사를 가지거나, yesterday, tomorrow, today 처럼 그 의미의 일부에 before, after, next, last, this를 포함할 때 

I was busy (*on) that day/ last Friday, the day before yesterday. 
We will be in San Diego (*on) this Sunday/next Sunday. 
I'm going there (*on) tonight/(*for) next week. 

6. 때를 나타내는 명사구가 every, all 등 수량사를 가질 때 

She goes to church (*on) every Sunday. 
We stayed in Reno (*for) all week.