切断正常供电电源,检查火灾应急照明和疏散指示标志是否在内自动转换进入点亮状态。
A、5s
B、15s
C、30s
D、50s
参考答案:A
为了绿化城市,某街道要栽种一批树苗,这批树苗的成活率是80%~90%,如果要保证成活720棵,至少要栽种( )棵.
A.648
B.900
C.800
D.576
What happened to the city after the mass move
A.Housing costs decreased.
B.Crime rate was much lower than before.
C.All business moved out.
D.Cities declined.