______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
Because of the heavy traffic，it was already time for lunch break ________ she got to her office.(2010·四川)
#29962
A
since
B
that
C
when
D
until
---- When did the couple die? ---- It was on May 12 _______ the earthquake hit Wenchuan County.
#33030
A
that
B
which
C
when
D
what
There is a popular opinion among teachers _____ reviewing the lesson after class can help students learn better.
#33799
A
who
B
whose
C
that
D
which