Nowadays scientists are working hard to find out ______ to do with air pollution.
#37100
A
how
B
why
C
when
D
what
推荐题目
—Every day, my mother tries to spare some time to chat with me ______ she is very tired after a wholeday’s hard work.—How great she is!
#43252
A
unless
B
whether
C
although
D
until
Father won’t allow me to play outside_______ I wash up the dishes.
#36869
A
if not
B
if
C
unless
D
because
Jane’s dad is getting old, so she has go back home to see him ______ it’s convenient.
#36208
A
because
B
whenever
C
although
D
unless
_______carefully you write, _______ mistakes you’ll make.
#43388
A
The more, the fewer
B
The less, the fewer
C
The less, the more
D
The more, the less