我国消防工作的方针是（）。
A.安全第一，预防为主
B.防消结合，综合治理
C.预防为主，综合治理
D.预防为主，防消结合
参考答案：D
Twenty students in this university _________ to Australia to study last year, and more students are
expecting to have the chance next year. [ ]
A. are sent
B. were sent
C. will send
A．可燃冰是可再生能源
B．可燃冰的能量来自亿年前的太阳能
C．可燃冰是核聚变反应生成的
D．可燃冰燃烧时核能转化为内能
