热力除氧器,除了将水加热至沸点外,为了使氧气自水中较快分离出来,还必须使()。
A、水流速降低
B、水中溶解杂质量减少
C、水分散成小水滴
D、水流速加快
参考答案:C
产后6个月,哺乳,已恢复月经2个月,对橡胶过敏,宜选择的避孕方法是()
A.宫内节育器
B.阴茎套
C.短效口服避孕药
D.长效口服避孕药
E.输卵管、输精管结扎术
—I'm going to study engineering in Tsinghua University tomorrow. —().
A.All the best in your study
B.All the best with your study
C.All the best in your business
D.All the best in your new job