可燃混合气燃烧后生成的废气,必须从气缸中(),以便进行下一个工作()。
参考答案:排除;循环
-What do we need to buy?
-________.
A.Two kilos of potatoes and two packets of salts
B.Two kilos of potatoes and two packet of salt
C.Two kiloes of potatos and two packets of salt
D.Two kilos of potatoes and two packets of salt
输卵管妊娠最常见的原因是
A.输卵管结扎术后再通
B.输卵管发育不良
C.子宫内膜异位症
D.慢性输卵管炎
E.孕卵外游