问题
选择题
—_____ do you go to school?
—At around 7:00. [ ]
A. What time
B. What
C. How
D. Where
答案
答案：A
搜题请搜索小程序“爱下问搜题”
—_____ do you go to school?
—At around 7:00. [ ]
A. What time
B. What
C. How
D. Where
答案：A
=5m，OB长为
=10m。两堵竖直墙的间距
=11m。滑杆A端用铰链固定在墙上，可自由转动。B端用铰链固定在另一侧墙上。为了安全，消防员到达对面墙的速度大小不能超过6m/s，挂钩与两段滑杆间动摩擦因数均为
=0.8。(
=10m/s2，sin37°=0.6，cos37°=0.8)