JTl型通用式机车信号在双机热备条件下,当主机故障时,切换至副机工作的切换时间应不大于()。
A.0.25s
B.0.5s
C.0.6s
D.1s
参考答案:B
下列物业经济指标中,不属于写字楼物业经营管理绩效评价的指标是()
A、物业经济指标
B、服务满意度
C、物业品牌化
D、市场占有率
The earthquake in Japan, measuring 9.0 on the Richter Scale, was so violent cause a series of explosions of the nuclear reactors in several power stations.
A.to
B.that
C.as to
D.as that