听力原文:W: What is the deadline for the term paper, sir?
M: Since it should be about 10 type-written pages long, you can hand it in next week.
Q: What is the probable relationship between the two speakers?
(16)
A.Manager and clerk.
B.Doctor and nurse.
C.Director and secretary.
D.Professor and student.
已知-对外啮合标准直齿圆柱齿轮传动的标准中心距a=150mm,传动比i12=4,小齿轮齿数Z1=20。试确定这对齿轮的模数m和大齿轮的齿数Z2、分度圆直径d2、齿顶圆直径da2、齿根圆直径df2,