把句子重新排列成一段话。
A. Two.
B. How many?
C. May I have some hamburgers?
D. Good morning.
E. Can I help you?
____
看拼音写词语。
ɡuǎi wān
ɡuǎi jiǎo
wān qū
wān dào
chuí luò
chuí zhí
duō kuī
chī kuī
xiǎo ɡǒu
lánɡ ɡǒu
qī ɡuǎi bā wān
一轻杆一端固定质量为m的小球,以另一端O为圆心,使小球在竖直面内做半径为R 的圆周运动,如图所示,则下列说法正确的是( )