问题
选择题
I like flowers. I hope to study at a school ____ many flowers and trees in it. [ ]
A. in
B. with
C. on
D. by
答案
答案：B
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I like flowers. I hope to study at a school ____ many flowers and trees in it. [ ]
A. in
B. with
C. on
D. by
答案：B
、
两平行板间存在着水平向右的匀强电场
，
，
正对右侧竖直屏上的
点，以
轴水平、
轴竖直)。
，
和匀强磁场
。一个带正电的可视为质点的微粒从紧贴
点以某一
竖直向上射出，恰好从小孔
，初
，磁感应强度
，
)。
。求：