进入灾区前必须检查氧气呼吸器,氧气压力不得低于多少?
参考答案:
18mpa。
After playing football for more than half an hour, the students took ______ rest.
A.a ten--- minute
B.a ten minute’s
C.a ten-minutes’
D.a ten-minute’s
土地管理的方法中,行政方法比法律方法具有更大的强制性,严肃性和权威性。