海洋中的生物死亡后,含有()、碳酸钙的骨骼或贝壳堆积在海底,可以形成磷质岩、硅质岩和石灰岩等
A.钙、磷
B.硅、磷
C.硫、磷
D.钾、磷
参考答案:B
--- Mike is really a polite boy.
--- Yes. He ________ “Good morning” to me every day.
A.speaks
B.says
C.talks
D.tells
C125M×3-2RH离心式压缩机的排气压力过低原因及处理?