36. The word “themselves” in line 4 refers to ____.
(A) molecules
(B) bacteria
(C) substances
(D) viruses
答案:登入後查看
統計: A(0), B(0), C(0), D(3), E(0) #3313209
統計: A(0), B(0), C(0), D(3), E(0) #3313209