吞服脊髓灰质炎三价疫苗糖丸时必须用冷开水送服。()
参考答案：对
---- How are getting on with your English study?
----_________.
A．Thanks
B．Good , thank you
C．Quite well, thank you
D．Very good
下面列出的四种存储器中，易失性存储器是 ( )
A．RAM
B．ROM
C．FROM
D．CD-ROM
