题干

下列关于离心现象的说法错误的是(   )

A:离心式水泵利用了离心运动的原理

B:提高洗衣机脱水桶的转速,可以使衣服甩得更干

C:转动带有雨水的雨伞,水滴将沿圆周半径方向离开圆心

D:为了防止事故,高速转动的砂轮、飞轮等不能超过允许的最大转速

上一题 下一题 0.0难度 选择题 更新时间:2017-08-24 12:19:30

答案(点此获取答案解析)

C

同类题5

请认真阅读下面短文,用英语回答短文后的问题,并将答案写在横线上。


Book Review by Patricia Ann Turner

    It is school holiday time and Mitch Morrow's family have just moved to a new home in a new place. Mitch can't stop worrying about what his new school is going to be like. He  is not even sure about the neighbours. Next door live the Bull family and they have two children, Di and Bruce.  

    The older of the two,  Bruce,  is a large boy,  about Mitch's age. Mitch. Watches him carry big rocks. He looks really strong and unkind. Mitch gives him the name Bruiser(彪形大汉) because he has a black eye. Did he get it in a fight? Mitch imagines all the worst possible things about Bruiser. He is probably the class bully (恶霸). In his mind Mitch thinks of him as the enemy.

    Things seem to get more worring for Mitch. He finds out he will be in the same class as Bruiser. Then on the first day of school he learns that Bruiser is his buddy for the day.

    This is a lovely story for young readers to read or listen to. It has a wonderful message for all children about facing their fears —real and imagined.

    The pictures in the book catch the worry Mitch feels and make Bruiser rcally look like a bad guy.

    My only complaint is the colour of the printing of the text. Why there are pages of different coloured print I cannot tell. They may create problems for children with poor eyesight.

    I give it four stars.