单纯性龈炎又称( )
A．坏死性龈炎B．龈 * * 炎C．慢性龈缘炎D．肥大性龈炎E．以上都不对
参考答案：C
Low-carbon lifestyle is of great benefit to improve the world environment．_________can be
enjoyed from it until you have a deep understanding of it，however．
A．Something
B．Nothing
C．Few
D．Much
下列加密算法中，可以用于数字签名的是______。
A．DES B．3DES C．RSA D．IDEA
