以下是Ca的生理作用的是（）
A、形成血红蛋白和肌红蛋白必须的
B、与细胞生物氧化过程密切相关
C、可以促进红细胞成熟
D、防止感染寄生虫
参考答案：C
用所给词的适当形式填空。
小题1: My aunt goes shopping ____________（two) a week.
小题2: A lot of ____________ (visit) visited our school last year.
小题3: Mary had much fun ____________ (play) at the aquarium with her mother two weeks ago.
小题4: I think math is the ___________ ____________ (important) of all the subjects.
小题5: Please don’t forget ___________ ____________ (finish) your homework first.
R134制冷剂的化学分子式。
