两种可燃性液体的混合物的闪点，一般在这两种液体闪点之间，并（）这两种物质的平均值。
A、高于
B、等于
C、低于
参考答案：C
E-mail, as well as the telephone, ___________ an important part in daily communication.
A．is playing
B．have played
C．are playing
D．play
钴铬钼合金的最显著特点是
A．价格低
B．耐蚀性好
C．耐磨性好
D．生物相溶性好
E．耐疲劳性好
