The flu is believed _____ by viruses tha
题型:选择题
问题:
The flu is believed _____ by viruses that like to reproduce in the cells inside the human nose and throat. [ ]
A. causing
B. being caused
C. to be caused
D. be have caused
The flu is believed _____ by viruses that like to reproduce in the cells inside the human nose and throat. [ ]
A. causing
B. being caused
C. to be caused
D. be have caused