若a+b=4,则a2+2ab+b2的值是( )
A:8
B:16
C:2
D:4
我省今年部分城市由于大量使用化石燃料,增大了空气中PM2.5的浓度,出现雾霾天气.
(1)化石燃料包括:煤、石油、____ .
(2)如图是对燃烧条件及过程的探究.A中蜡烛燃烧一会熄灭,B中蜡烛正常燃烧,A、B实验探究燃烧的条件是____.C实验应用的灭火原理是____ .
(3)D实验中小碟底部有蜡烛不充分燃烧产生的炭粒,石蜡和汽油都是石油的产品,为了减少汽车PM2.5颗粒物排放,你对燃油汽车企业的发展提出的建议是____ .
关于挫折和创新的关系,下列说法正确的是 ( )①人类文明在不断创新中完善 ②挫折激励创新,创新战胜③克服困难和挫折,需要开拓进取,勇于创新 ④创新是民族进步的灵魂,是国家兴旺发达的不竭动力
I'm an Chinese girl. My name is Rose. I have a brother. His name is Tom. Tom and I are in the same school. I often go to school by bike. Tom usually⑴w__________ to school. We both(两个都) have lunch at school and we like Chinese food very much. After school, Tom always plays basketball with his classmates. ②I always speak Chinese because I like Chinese best. I go home at about five o'clock in the afternoon. But Tom goes home late, at about a quarter past seven. My parents are both teachers. They teach for many years in Beijing. We like China very much.