最早把信息作为科学对象来加以研究的是在（）领域。
A、通讯
B、基因工程
C、物理学
D、信息管理
参考答案：A
Mrs Smith ______ a teacher. But she doesn't do that job now. [ ]
A. used to be
B. was used to be
C. has been
D. was used to doing
铣刀直径50㎜、每分钟回转数200，则切削速度为31.4m/min。（）
