The distance _______ the particle moves in that time is the circumference 2πR of its circular path.
A、when
B、where
C、which
D、/

A.买方叫价交易
B.卖方叫价交易
C.赢利方叫价交易
D.亏损方叫价交

A.材料弹性模量小则更易失稳
B.压杆的截面小则更易失稳
C.压杆的长度小则更易失稳
D.两端铰接杆比两端固定杆更易失稳