The flu is believed ________ by viruses
题型:选择题
问题:
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
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