The flu is believed __( )by viruses that like to reproduce in the cell inside the human nose and throat.
( )
A.causing B.being caused C.to be caused D.to have caused正确答案C
The flu is believed __( )by viruses that like to reproduce in the cell inside the human nose and throat.
( )
A.causing B.being caused C.to be caused D.to have caused正确答案C