The story was written in _____ easy English ____ even the seven-year-old boy could understand it.
A:very, that
B:so, that
C:such, that
D:too, to
不符合可持续发展理念的做法是( )
如图所示,细绳长为L,吊一个质量为m的铁球(可视为质点),球离地面的高度h=2L,绳所能承受的最大拉力为1.5mg,绳的上端系一质量不计的环,环套在光滑水平杆上,现让环与球一起以速度v= gL 向右运动,在A处环被挡住而立即停止,A离墙的水平距离也为L,求: