—Sorry, I _______. I will go travelling with my parents.
A:can't
B:couldn't
C:don't
D:didn't
填入下面横线处的几句话,排列最恰当的一项是( )
连续几个月埋首于砖块般的典籍中之后, ,我知道,这是不同于案头年龄的另一种年龄在捣乱了。
Mrs. Li gets up at 6:30. She gets up very early every day.
如图1所示,修正带是通过两个齿轮的相互咬合进行工作的.其原理可简化为图2所示模型.则A、B两点具有相同的( )