社区卫生宣传活动可通过
A.口腔健康咨询B.捷径调查C.问卷调查D.制定口腔保健计划E.口腔预防保健措施
参考答案:A
Some women _ _ a good salary in a job instead of staying home, but they decided not to work for the sake of the family.
A.should make
B.should have made
C.would make
D.could have made
A、B、C、D、E五种物质之间的变化关系如图所示。其中B、C、D为单质,C为钢铁的主要成分。试回答:
(1)A、D的化学式是:A ___________; D___________。
(2)请写出C→B、和C+D→E的化学方程式:
C→B :______________________________________________
C+D→E :___________________________________________