单项选择题
A.be less than
B.be larger than
C.be as large as
D.not be so large as
单项选择题 The position of the piston parts in relation to each other is secured by means of （） and a dowel pin in the crown.
单项选择题 The position of the piston parts in relation to each other is secured by means of （） in the crown.
单项选择题 The position of the interface between oil and water within the centrifuge is achieved by the use of （）.