题干
— ____ did you get there? — By ___ a taxi.
A： How; taking
B：How take
C：How; took
D：What; taking
答案(点此获取答案解析）
A
— ____ did you get there? — By ___ a taxi.
A： How; taking
B：How take
C：How; took
D：What; taking
平面内有一个以
为圆心、半径R=0.1m的圆，P为圆周上的一点，
两点连线与
轴正方向的夹角为
。若空间存在沿
轴负方向的匀强电场，场强大小
，则