随着石油沥青牌号的变小,其针入度和软化点有何变化()?
A.针入度变小,软化点降低
B.针入度变小,软化点升高
C.针入度变大,软化点降低
D.针入度变大,软化点升高
参考答案:B
怎样进行叶轮给煤机的操作?
The first year of the college life is a very complex ______ period, and the more fully the freshmen prepare for it, the better.
A.transmission
B.transposition
C.transformation
D.transition