KP20-10表示普通反向阻断型晶闸管的静态正向平均电流是()。
A、20A、
B、2000A、
C、10A、
D、10000A、
参考答案:A
--How did he get infected?
--She ____the viruses without any protection.
A.exposed to
B.had exposed to
C.was exposed to
D.had been exposed
—The pants are very nice. Can I try __________?
—Sure.[ ]
A. on them
B. them on
C. it on
D. on it