题目内容
(请给出正确答案)
[单选题]
When carbon is added to iron in proper _____ the result is steel.
A.rates
B.densities
C.proportions
D.thicknesses
查看答案
如果结果不匹配,请 联系老师 获取答案
A.rates
B.densities
C.proportions
D.thicknesses
A.正确
B.错误
B.found for
C.found off
D.found against
B.are crossing
C.crossed
D.is cross