Air pollution is getting more and more serious, so we must take action it is too late.
#31510
A
before
B
after
C
until
D
when
推荐题目
Dr. Black comes from either Oxford or Cambridge. I can’t remember _____.
#30800
A
who
B
there
C
which
D
what
The field research will take Joan and Paul about five months; it will be a long time ____ we meet them again.
#79980
A
after
B
before
C
since
D
when
We made it possible the task would be finished ahead of time within three weeks.
#29955
A
what
B
that
C
which
D
how
Along with the letter was his promise he would visit me the New Year.
#30623
A
which
B
that
C
what
D
whether
My partner wants to keep the company small _____ I’d like to expand it.
#30799
A
and
B
or
C
however
D
while