把两个句子改写成一个句子。
1. I didn't understand... What does my teacher say?
__________________________________________________________________
2. Could you please tell me...? Where will the meeting start tomorrow morning?
__________________________________________________________________
3. Would you please tell me...? What should we do next?
__________________________________________________________________
4. They asked me... Where have I been during the May Day holidays?
__________________________________________________________________
5. He said that... The earth goes round the sun.
__________________________________________________________________
的斜面处于竖直向下的匀强电场中，在斜面上某点以初速度
水平抛出一个质量为m的带正电小球，小球在电场中受到的电场力与小球所受的重力相等，地球表面重力加速度为g，设斜面足够长．问：小球经多长时间落到斜面?
