【单选题】The piston of a natural-gas vehicle moves up and down by the power of ______.
B.
the four-stroke engine
C.
the air in the cylinder
D.
the heat of natural-gas burning
【判断题】标准C51的CPU可以进行的运算有:算数运算、逻辑运算、位操作运算。
【判断题】肺炎支原体肺炎抗生素治疗首选红霉素。()
【单选题】AT89C52单片机的ALE引脚是( )。