______environmental damage is done，it takes many years for the ecosystem to recover.
#80690
A
Eyen if
B
If only
C
While
D
Once
推荐题目
I came to the music hall, I got addicted to the tone.
#32946
A
The first time
B
For the first time
C
First time
D
First
I don’t believe we’ve met before, ________ I must say you do look familiar.
#31797
A
therefore
B
although
C
since
D
unless
Scientists say it may be five or six years _______ it is possible to test this medicine on human patients.
#33536
A
since
B
after
C
before
D
when
The fireman succeeded in saving all the people in the house on fire, _______they knew they were in great danger themselves.
#30761
A
because
B
since
C
unless
D
though
He made a mistake, but then he corrected the situation ________ it got worse.
#32998
A
until
B
when
C
before
D
as