We should protect the earth,         we will have no water to drink.
#58271
A
so
B
or
C
and
D
but
推荐题目
 I don’t like running, _____I like swimming. 
#56237
A
and    
B
but   
C
with   
D
so
Don’t stop working _____ twelve. 
#58157
A
to
B
at
C
when
D
until