氮气是一种无色无味的惰性气体。

I love to tell the story about how I met my best friend---- Tiger. We met at the school fair. Each year, all the fourth-grade classes hold a school fair. Everyone in the fourth-grade works at the fair. Some sell ice cream, drinks and snacks. Others take care of the little children who ride the rides.

I got the second job and I’ve never regretted it, because that’s where I met Tiger.

My job was to help little children get on the back of a little horse. I kept telling the children to wait their turn and holding ice cream for them while they rode about. One thing was clear to me. I was growing older and should be more responsible.

Suddenly, a boy came to the horse. He took the little horse’s reins! The horse stopped, and the girl on its back started to fall. I was trying to reach the girl when I saw Tiger go by my legs. It held the horse’s reins and pulled the horse away from my legs. I caught the girl just before we both hit the ground. The girl sat on top of me. She was laughing at the ice cream on my face. The horse’s reins were in Tiger’s mouth!

Thanks to Tiger’s fast action, I saved the little girl. We were both heroes. And Tiger, the fastest dog I’ve even known became my new best friend.

小题1:According to the passage, __________ work at the fair.    

A．ice cream sellers

B．all the school children

C．little boys and girls

D．the fourth-grade students小题2:The writer’s job was to __________.

A．take the little horse’s reins

B．look after the children

C．get on the back of the horse

D．ride with little children小题3:As soon as the little horse stopped, the girl __________.

A．started to fall

B．laughed at the writer

C．hit the ground

D．sat on top of the writer小题4:Tiger helped to save the little girl on the horse by __________.

A．going fast by the writer’s legs

B．trying to catch the little girl

C．holding the reins with its mouth

D．riding the little horse around小题5:From the passage, we know that __________.

A．Tiger was a actually a brave dog

B．Tiger wanted to become a hero

C．the writer didn’t want to grow up

D．the writer regretted working at the fair

薄壁细胞中含有针晶束的有

A．天麻

B．巴戟天

C．麦冬

D．何首乌

E．秦皮

改革，哪怕是仅仅一小步的改革，也都是需要______的。倘若一种行为从一开始就定错了目标，或者更有甚者，如果这种行为从一开始就没有定下目标，只是______地走一步算一步，那完全是有可能“摸着石头过不了河”的!
填入划横线部分最恰当的一项是( )。

A．远见 随波逐流
B．勇气 得过且过
C．魄力 漫无目的
D．目标 随遇而安

替代性强化是班杜拉的社会学习理论中的一个概念，指一种榜样替代的强化。一般说来，学习者如果看到他人成功的行为、获得奖励的行为，就会增强产生同样行为的倾向；如果看到失败的行为、受到惩罚的行为，就会削弱或抑制发生这种行为的倾向。这样一来，对榜样行为的强化，通过学习者的观察、体验而可以转化为学习者自身的动机作用。
根据上述定义，下列符合替代性强化规律的是( )。

A．小亮同学因为乐于帮助他人而获得了“校德育标兵”的称号后，班里就形成了一股助人为乐的班风
B．妈妈发现小虎撒谎就批评了他，小虎以后再也不对妈妈撒谎了
C．小波以前喜欢到老爷爷家偷枣而自得其乐，后来他每次去，老爷爷都给他满满的一大袋，小波觉得没意思，就再也不去了
D．三班在歌咏比赛中拿到了全校第一，同学们觉得这是大家共同努力的结果，就在放学后去庆祝了一番

生物的结构总是与其生活环境相适应，下列对不同动物的结构与其生活环境相适应的叙述中，错误的是（）

A.鱼用鳃呼吸适应水中生活

B.家鸽前肢变成翼适应空中飞行生活

C.昆虫有外骨骼适应陆地干燥生活

D.雄蛙有鸣囊适应水陆两栖生活