【单选题】25Our professor meets his advanced students once a week to hold a(n) _______ on adult development. He always invites us to attend it too.
【简答题】周转轮系是指传动时,轮系中至少有( )个齿轮的几何轴线位置不固定,而是绕另一个齿轮的固定轴线回转
【单选题】Our professor meets his advanced students once a week to hold a(n) ______ on adult development. He always invites us to attend it too.
【单选题】Our professor meets his advanced students once a week to hold a(n) _______ on adult development. He always invites us to attend it too.