问题
选择题
When you go outing with your sisters, you must see to ____ that they are safe.[ ]
A. everything
B. it
C. them
D. yourself
答案
答案：B
搜题请搜索小程序“爱下问搜题”
When you go outing with your sisters, you must see to ____ that they are safe.[ ]
A. everything
B. it
C. them
D. yourself
答案：B
=3.20cm，
=4.52cm，
=8.42cm，
=9.70cm，则木块的加速度大小
= m/s2（保留两位有效数字）。
= （重力加速度为g，木块的加速度为