某站出现R-LOF告警的原因可能是()。
A.接收信号衰减过大
B.对端站发送信号无帧结构
C.本板接收方向故障
D.本端支路故障
参考答案:A, B, C
老师指出小明的缺点和错误,要求小明改正,但小明感到老师讲的与事实不符。在这种情况下,小明可以[ ]
A.当面顶撞老师
B.老师讲老师的,我想我的,不用哕唆
C.只管点头称是
D.实事求是地将自己的想法告诉老师,与老师进行沟通
- What's wrong with you, Madam?
- I've lost my valuable painting. But a week had gone by _______ I knew it was missing.
A.while
B.since
C.until
D.before