If ____ in, viruses can result in illness or even death.
#88250
A
breathe
B
breathing
C
breathed
D
to breathe
推荐题目
_______ as “a class of one ”, independent learning enabled you to study at your own pace.
#96491
A
Describing
B
Described
C
To be described
D
Being described
Time ____ never comes again. So we’d better make full use of our time. 
#96385
A
losing
B
lost
C
being lost
D
having lost
Which materials can be thrown into the sea _______on the nature of them?
#92428
A
depended
B
depending
C
to depend
D
depends