面谈检查的环境应该安静,理想的状况是只有检查者和被检查者两人()
参考答案:对
用所给单词的适当形式填空。
1. Is it possible ______ (save)in any situation?
2. Aron still goes mountain ______ (climb),
3. The poor girl hurt ____ (she) in the accident.
4. They have much homework ____ (do).
5. The peanut was ____ (safe) removed by the doctor.
某带电小球从空中的M点运动到N点,受到重力、空气阻力和电场力的共同作用。其中重力对小球做功4.5J,小球的动能增加了3J,则( )
A.小球的重力势能增大7.5J
B.小球克服空气阻力做功为1.5J
C.小球的机械能增加了1.5J
D.若电场力做功为2J,则小球克服空气阻力做功为3.5J