【单选题】He is always here. It's ______ you've never met him.
【判断题】采用直缩法生产PET树脂,原料对苯二甲酸与乙二醇的酯化反应温度通常是在乙二醇的常压沸点以下。
【单选题】听力原文:When are we meeting? (A) Tomorrow afternoon. (B) I've never met him before. (C) No, I don't know when it's due. (13)
【单选题】'Have you met Bill's brothers?''I've met one. I didn't know he had_________.'
【单选题】46某二叉树共有150个结点,其中有50个度为1的结点,则
【简答题】He is always here it’s ________ you’ve never met him. A) unique B) strange C) rare D) peculiar
【单选题】—Believe it or not, I have met him before. —No kidding? ________ you've never mentioned it?
【单选题】如图所示,细杆OA绕齿轮1的中心轴O转动,转速n已知。在细杆上安装有齿轮2、3,细杆转动过程中三个齿轮两两相互啮合,齿轮1固定不动,齿轮2、3转动。三个齿轮的半径r1、r2、r3已知,且r1=r3,求齿轮2、3各自的角速度。 【图片】
A.
n 2 =(2 r 1 + 3 r 2 )/ r 2 * n , n 3 =(2 r 1 + r 2 )/ r 2 * n
B.
n 2 =( r 1 + 2 r 2 )/ r 2 * n , n 3 = n
C.
n 2 =( r 1 + r 2 )/ r 2 * n , n 3 = 0
D.
n 2 =(2 r 1 + r 2 )/ r 2 * n , n 3 =2 n