锯割机械主要用于( )的工序中。
A.坯料制备
B.成型画线
C.精细加工
D.包装
参考答案:A
可同时累及两侧肾上腺的疾病有()
A.转移癌
B.结核
C.增生
D.嗜铬细胞瘤
E.以上都可以
What may be the oldest fossil footprint yet found was discovered in June 1968 by William J. Meister, a non-professional fossil collector.
A.a part-time
B.a spare-time
C.an untrained
D.an amateur