01.16 since when before用法

1. It will be four years ______ he can join the army.

a. before b.if c.since d.when

Answer: a.before

易錯：c.since

分析：It will be +時間段+before+句子（一般現在時）=多久之後......才

2. This/that/it is the first time that+現在完成時

eg.This is the first time thatI have finished my homework before the last day of my summer vacation.

譯：這是我第一次在暑假的最後一天之前完成作業。

• It has been +一段時間+since+主語+一般過去時

eg.It has beentwo yearssinceIstayedin this university.

譯：我離開這所大學已經兩年了。

• It will be +一段時間+before+主語+一般現在時

eg.It will beyearsbeforeHaitianshaveaccess to clean water and proper sanitation.

譯：海地人能使用潔淨的水源、合適的公共衛生設施可能還需要幾年時間。

• It was/is +時間點+when

eg.It isten yearswhenwe last met.

譯：我們上次見面是在10年前。

• It is/ was +the +序數詞+time（that）+主語+現在/過去完成時

eg.It isthe thirdtimethatyou have been late this month.

譯：這是你這個月第三次遲到了。