AT89C51系列单片机由_____________字节片内RAM存储器,由_____________个16位定时器 ;有4个____________位并行口;P0,P1,P2,P3;有_______________个全双工的串行口;有____________个中断源。
[音频]Listen and fill in the blanks.Ruby got her first ( 1 ) payment, but instead of cash, she got a check. She didin't know how to use it. John advised her to ( 2 ) the check in a bank, and then pay her ( 3 ) by checks and get some cash with her ( 4 ) card. With the ATM, you can deposit or get money all over the city or the country, or even around the ( 5 ). You can even pay your bills( 6).