第1个回答 2009-09-30
for:
(prep)
表示时间的持续,后面加时间段,表示一段时间,多与带数词的名词连用,其谓语需用延续性动词。
We
have
been
leaning
English
for
two
years.
since:
(prep)
表示“自从过去某一时间点以来”,后面接点时间,强调动作或状态一直延续到现在,一般用现在完成时或现在完成进行时。
I
have
been
skating
since
9
o’clock.
How
long
have
you
been
doing
that?
Since
2
years.
I
have
been
collecting
kites
for
seven
years.
He
has
been
watching
English
movies
since
9
p.m.
I
have
been
listening
to
music
videos
since
1999.