下列物理量中,属于标量的是
A.力
B.加速度
C.功
D.速度
答案:C
力、加速度、速度都既有大小又有方向,都是矢量,ABD错;功只有正负,没有方向,所以是标量,C对。
句型转换(每空1分,共10分)
小题1:He often plays computer games after he finishes his homework.(变为否定句)
He often computer games after he finishes his homework.、
小题2:Jenny is staying with the old people this weekend.(改为一般疑问句)
Jenny with the old people this weekend?
小题3:They can go to school by bus.(对划线部分提问)
they go to school?
小题4:他昨晚没带钱,所以只能走路回家。(翻译句子)
He didn’t take money with him last night, so he go home on foot.
小题5:I am 30 years old. My friend is 30 years old, too.(合并为一句)
I’m _________ years old as my friend.
普通集中式空调系统的主要缺点是什么?