Key Words【关键词】
1．in prep．在……之后（用于将来时）
in l00 years 在一百年后
People will have robots in their homes in 100
years．一百年以后，人们家中会有机器人。

比较：after 在……之后（用于过去时，表示从过去某时间起一段时间之后）
He will come back in two hours．他两小时后会回来。

He came back after two hours．他是两小时后回来的
一般将来时In +一段时间，，[will do ], 用how soon 提问
一般过去式时间+ago last +时间after+时间
how long 意为“多久、多长时间”，主要是对一段时间进行提问，答语通常是（for）three days/weeks/months 等时间段，它可用于各种时态。

How long do you stay in Beijing every year? 每年你在北京住多久？
How long have they lived here? 他们住在这里有多久了？
—How long were you not at school last year? 去年你多久没上学？—About two weeks. 约两周。

How long will it take? 这要花多长时间呢？
how soon 意为“还要多久”，是对从某个基本时间到将来某动作结束或某动作发生这段时间提问，常用在一般将来时态的句子中，其答语通常是“in + 一段时间”。

—How soon can you finish the work? 还要多久你能完成这项工作？
—In half an hour. 半小时后。

how often 意为“多久……次、是否经常”，用来提问在某一特定的
时间进行某个动作的次数，答语通常是
always，usually，often，sometimes，once/twice a day/month 等。

—How often do you get to school very early? 你多久早到校一次？—Usually. 通常。

How often do you see a film? 你多久看一次电影？
—Once a month. 每月一次。

自我测试○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○
选择填空。

1.—did the meeting last? —About half an hour.
A. How soon
B. How long
C. How far
D. How much
2.—will Ezhou-Huanggang Bridge be finished? —In a few months.
A. How soon
B. How long
C. How often
D. How far
3.—will it take you to get to the post office?
—About half an hour.
A.How old
B.How long
C.How soon
D.How often
4.—do you write to your mother? —Once a month.
A. How many times
B. What time is it
C. How soon
D. How often
5.— a year does your school have sports meetings? —Twice a year.
A. How often
B. How soon
C. How long
D. How many times
答案：1.B 2.A 3.B 4.D 5.A
have gone to、have been to、have been in 区别
have gone to/have been to/have been in:
have gone to+地点“已去了…（还未回来）” -I can’t find those children, where are they?
-They have gone to the farm. (去了农场，不在这儿)
have been to+地点“去过…（原来去过，现在已回）”句尾常接次数或多
个地点
或 before，或句中常有 ever, never 等。

She has been to Qingdao three times. I have been to two big cities. Have you been to Dalian before? I have never / ever been to Dalian.
I have never been there before. Where have you been? 你去哪儿了？(此行省略了 to)
have been in + 地点，“已在…（多久了）”句尾常接 for + 时间段，或since + 时间点 / 一般过去时的句子。

Peter has been in China for a long time.
I’ve been here for 2 hours / since 2 hours ago. (此短语省略了 in)。