---We’ve seen many more days of blue skies recently. ---True. But back in 1998, ________ Beijing started its “Defending the Blue Sky” program, the city only ________ about 100 days a year.
#34101
A
which, sees
B
that, saw
C
when, saw
D
and, seeing
推荐题目
– I wonder how much you charge for your services.-- The first two are free ____ the third costs $30.
#80584
A
while
B
until
C
when
D
before
—She was late for the party.—That’s _________she had forgotten the exact time.
#31013
A
why
B
how
C
because
D
whether
___ most of the earth’s surface is covered by water, fresh water is very rare and precious.
#80429
A
As
B
Once
C
If
D
Although
I don’t believe we’ve met before, ________ I must say you do look familiar.
#31797
A
therefore
B
although
C
since
D
unless