早期诊断真菌性角膜炎的方法
A．B超
B．角膜刮片染色
C．PAS染色
D．角膜组织活检
E．免疫荧光染色
参考答案：B
—Hello, Mike. Where is our teacher?
—Oh, he _______ the library. He'll be back in a minute.[ ]
A. has gone to
B. has been to
C. went
D. will go
继电保护的作用是什么？
