若已知一个电阻两端加上400V的电压时,所消耗的功率为80W,那么当外加电压减少一半时,则消耗的功率为()W。
A.60;
B.40;
C.20;
D.10。
参考答案:C
It's ______ colder today than it was yesterday. [ ]
A. very
B. more
C. much
D. little
工程应尽量采用( )的技术,吸取科研新成果,体现先进技术和生产力水平。
A.安全
B.先进
C.成熟
D.适用
E.核心