低合金高强度结构钢原名为( )。
A. 普通低合金钢
B. 低碳钢
C. 普通钢
D. 高强工具钢
The ______ cycle of life and death is a subject of interest to scientists and philosophers a- like.
A. incomplete
B. exceeding
C. instructive
D. eternal
红外线加热,即把能量转化为波长( )μm的红外线辐射到焊件上。
A. 2~10
B. 2~15
C. 2~20
D. 2~25
Careful surveys have indicated that as many as 50 percent of patient do not take drugs ______ directed.
A. what
B. so
C. which
D. as