什么是爆炸极限?
参考答案:
当可燃性气体、蒸气或可燃粉尘与空气(或氧)在一定浓度范围内均匀混合,遇到火源发生爆炸的浓度范围称为爆炸浓度极限,简称爆炸极限。
—On May 12, ______ earthquake in China for more than 30 years hit Wenchuan, Sichuan.
—People in the areas are facing ______ and disease. But the whole nation is behind them. [ ]
A. biggest; death
B. the biggest; death
C. the big; dead
D. bigger; dead
如血糖控制良好,无其他合并症时,何时终止妊娠为宜
A.孕35~36周B.孕36~37周C.孕37~38周D.孕38~39周E.孕40周以后