- 搜标题
- 搜题干
- 搜选项
单项选择题
Which of the following is true of the detectors?A.They have not been sold to Africa.###SXB
A.They
B.
B.They
C.
C.They
D.
D.They
E.
B.
B.They
C.
C.They
D.
D.They
E.
