墨尔本文波雅思为大家讲解动词时态中现在完成时的语法应用。
. 现在完成进行时：形式：have/has been doing
含义：从过去某点一直重复或延续到现在。
国外烤鸭看这里：
国内烤鸭看这里：
Exam link
I won’t tell the student the answer to the math problem until he ___ on it for more than an hour.
A has been working B will have worked
C will have been working D had worked
It seems that oil ___ from this pipe for some time. We’ll have to take the machine apart to put it right.
A had leaked（v.泄露） B is leaking C leaked D has been leaking
阅读鉴赏
The revolution isn’t simply a matter of gentlemen reading other gentlemen’s e-mail. That kind of electronic spying has been going on for decades. In the past three or four years, the World Wide Web has given birth to a whole industry of point-and-click spying.
Americans have been migrating south and west in large number since World War II, and pattern still prevails.
In recent years, railroads have been combining with each other, merging into super systems, causing heightened concerns about monopoly.
The revolution isn’t simply a matter of gentlemen reading other gentlemen’s e-mail. That kind of electronic spying has been going on for decades. In the past three or four years, the World Wide Web has given birth to a whole industry of point-and-click spying.
