The researehers delermine what type of plants the virus can infect(感染) and_________insects can carry the virus.
| A．those | B．why | C．which | D．how |
He told me that he had two girl-friends, neither of _______ knew anything about the other.
| A．whom | B．them | C．which | D．who |
He asked a lot of questions, and none of ______ was easy to answer.
| A．them | B．which | C．what | D．that |
He asked a lot of questions, none of ______ was easy to answer.
| A．which | B．them | C．what | D．that |
6. He had thousands of students, many of ______ gained great success in their own field.
| A．whom | B．them | C．which | D．who |
I met the fruit-pickers, several of _______ were still university students.
| A．that | B．who | C．them | D．whom |