A:把摆球的质量增加一倍,其周期变小
B:把摆角变小时,则周期也变小
C:此摆由O→B运动的时间为T/4
D:摆球B→O时,动能向势能转化
用所给词的适当形式填空
My watch doesn’t work. It needs to ____ .Who ____ away my pen? I can’t find it.Lucy said she____ the primary school the next month. It’s correct____ strangers come into your house. It’s ____ to join a charity walk than to play computer games.
— We have got _______ sweet potatoes. What about you?
— We haven't got ________ sweet potatoes.