起重机紧急断电保护的作用，主要是在（）或（）情况下用来切断联锁保护电路。
参考答案：事故；紧急
It is reported that many a new house ______ at present in the disaster area.
A．are being built
B．were being built
C．was being built
D．is being built
领导者要敢于和善于破旧立新，推陈出新，要有永不满足的态度，这属于现代领导的( )。
A．竞争观念 B．信息观念C．改革创新观念 D．效益观念
