Experts are trying to work out a plan to deal with the problems caused by global warming ______ it is too late.
#31459
A
when
B
if
C
before
D
until
推荐题目
Several weeks had gone by _______ I knew the painting was missing.
#32417
A
as
B
since
C
until
D
before
—It’s a long time________I saw you last.—Yes，and what a pity it is now that it will be a long time________we see each other again.
#31909
A
before；since
B
since；when
C
since；before
D
when；before
I like Emy, ________ she can be annoying（烦人的）at times.
#33422
A
even though
B
now that
C
as though
D
as long as
----How soon will you send the book to me? ----It will be two days _______ you receive my book.
#33944
A
before
B
that
C
since
D
when
We were swimming in the lake _______ suddenly it began to rain heavily.
#30962
A
when
B
while
C
until
D
before