题目内容
21、
I was out of town at the time, so I don’t know exactly how it _______.
A. was
happening B.
happened C.
happens D. has
happened
试题答案
21、C
解析：考查代词及其含义，由语意：他们必须面临的其中一个问题就是公共卫生问题，只有that,可以代替the problem.
I was out of town at the time, so I don’t know exactly how it _______.
A. was happening B. happened C. happens D. has happened
查看习题详情和答案>>I was out of town at the time, so I don’t know exactly how it _______.
A. was happening B. happened C. happens D. has happened
查看习题详情和答案>>I was out of town at the time, so I don’t know exactly how it _______.
A. was happening B. happened C. happens D. has happened
查看习题详情和答案>>I was out of town at the time, so I don’t know exactly how it _______.
A. was happening B. happened C. happens D. has happened
I was out of town at the time, so I don’t know exactly how it _______.
| A．was happening | B．happened | C．happens | D．has happened |
I was out of town at the time, so I don’t know exactly how it _______.
A. was happening B. happened C. happens D. has happened
查看习题详情和答案>>
I was out of town at the time, so I don’t know exactly how it _______.
A. was happening B. happened C. happens D. has happened
查看习题详情和答案>>
I was out of town at the time, so I don’t know exactly how it _______.
A. was happening B. happened C. happens D. has happened
查看习题详情和答案>>