异步电动机由______和______两个基本部分组成。
参考答案:定子;转子
阅读理解。
根据短文内容,判断句子正(T)误(F)。
Maria is an English girl. She is ten years old. She is in Shanghai with her parents. She studies in a
middle school(中学).She is in Class Six, Grade Seven. Maria's father is our Chinese teacher.He is a
Beijing Opera fan. He often goes to see Beijing Opera with Maria. And Maria likes Beijing Opera, too.
She thinks it is very interesting. She also thinks she can learn about Chinese history. But Maria's mother
doesn't like Beijing Opera. She thinks it is very boring. She likes comedies. She thinks they are very
exciting.
( )1. Maria is in England now.
( )2. Maria's mother is a Beijing Opera fan.
( )3. Maria's mother is our English teacher.
( )4. Maria also likes Beijing Opera.
( )5. Maria's mother likes comedies.
阅读材料,分析回答下列问题。(6分)
材料一:哈尔滨目前水资源严重短缺,城区水资源人均占有量只有180立方米,约为全国人均水平的十五分之一。洗车行每天要浪费掉近2000吨的自来水,足够一万多居民的日常用水。上游城市排放的污水和地表径流形成的水污染造成松花江饮用水源地的污染。
材料二: 雾霾期间,我国北京上海等几十个城市pm2、5(大气中的细颗粒物)浓度最高值接近1000微克/立方米,空气质量极差。空气质量的高低,与空气中所含污染物的数量有关,一方面受自然因素的影响,另一方面受人类活动的影响。
材料三:
(1)阅读材料一,哈尔滨水资源存在的问题主要有 (两点)
(2)根据材料三,我们要坚决守住 亿亩耕地,确保13亿人口的吃饭问题。请为切实保护耕地提出合理化建议:
(3)阅读材料二,空气质量的好坏与气象条件关系密切,北京的气候特点是夏季炎热多雨,冬季 。
(4)作为我国的首都,北京地区的环保不容忽视,请结合材料二列举:人类哪些活动会影响空气质量?