实施接零保护的系统，应将用电设备外壳接零线接至漏电断路器后面的零线上，这根连接线能接入漏电断路器。
参考答案：错
消化性溃疡病的主要临床表现是()
A．持续性上腹痛
B．食欲不振、上腹部不适
C．反酸、嗳气
D．恶心厌油
E．慢性、周期性、节律性上腹痛
She was in hospital for about half a year. He felt as if he was ________ from the outside world. [ ]
A. cut out
B. cut off
C. cut up
D. cut through
