In the past several weeks, many cities in Northern China        from heavy fogs and  severe cold.
#99857
A
had suffered
B
have been suffering
C
were suffered
D
suffered
推荐题目
Don't get that ink on your shirt, for it______. 
#104325
A
won'twashout
B
won'tbewashedout
C
isn'twashedout
D
doesn'twashaway
—How did she get infected?  —She ____ the viruses without any protection.
#101750
A
exposed to
B
had exposed to
C
was exposed to
D
has exposed to