5.Experts think we won't have clean water to drink unless something(b )soon,but much remains( b)about environment protection.
a.would be done,doing
b.is done,to be done
c.will be done,to be
d.is done,to do
remainto be done 固定搭配
第一空条件壮语从句,一般时,第二空to be done 表示要去做,而且是被完成
5.Experts think we won't have clean water to drink unless something(b )soon,but much remains( b)about environment protection.
a.would be done,doing
b.is done,to be done
c.will be done,to be
d.is done,to do
remainto be done 固定搭配
第一空条件壮语从句,一般时,第二空to be done 表示要去做,而且是被完成