锅炉效率是指()利用热量占()热量的百分数。
参考答案:有效、输入
— The authors of computer viruses are geniuses.
— I agree. They can apply their wisdom to other net technology from _____ human beings can benefit. [ ]
A. that
B. which
C. what
D. where
数字证书的含义、分类和主要用途,所采用的密码体制?