当水的质量数小于多少时,认为是痕迹?()
A、0.01%
B、0.02%
C、0.03%
C、0.05%
参考答案:C
When _____ who is their best friends, the boys usually hesitate before responding.
A.asking
B.asked
C.ask
D.to ask
一台计算机的配置标有PIV-800,其叶800代表( )。
A.CPU主频B.计算机价格C.硬盘容量D.以上均不对