下列生物碱碱性最强的是( )A．酰胺B．季铵C．仲胺D．伯胺E．吡咯类

阅读理解。

     Mrs Smith has a small garden behind her house, and in the spring she plants some vegetables in it.

he looks after them very carefully, and when the summer comes, they look very nice.

     One evening, Mrs Smith looks at her vegetables and says, "Tomorrow I am going to pick them.

"But early in the next morning, her son Jim runs in and shouts (喊), "Mum! Mum! Come quickly! Our

neighbour's duck is eating our vegetables in the garden!"

     Mrs Smith runs out ,but it is too late. All the vegetables are finished! Mrs Smith cries(喊)and her

neighbourhood is very sorry, but that is the end of the vegetables.

     One day before Christmas, the neighbourhood brings Mrs Smith a nice and fat duck ,and on the

duck's back is a piece of paper with the words, "Enjoy your vegetables."

1. The vegetables in Mrs Smith's garden grow _____

A. fast  

B. fine  

C. bad

2.The next morning the neighbourhood' duck _____

A. goes into the garden

B. eat up the vegetables

C. is finished

3.The neighbourhood feels very _____ for that.

A. happier  

B. glad  

C. sorry

4. One day before Christmas, the neighbourhood brings Mrs Smith _____

A. a big duck  

B. a small duck  

C. a nice and fat duck

5. What's on the duck's back?

A. Some money.  

B. Some vegetables.  

C.A note (便条).

某同学用足量氯酸钾与二氧化锰的混合物制取氧气，快速收集一瓶氧气后发现产生气体速率明显下降（实验情况如右图），接下来他应该

A．将酒精灯位置升高

B．将酒精灯向右微移

C．再向试管中加入氯酸钾

D．再向试管中加入二氧化锰

财政是国家凭借政治权力而进行的社会产品分配。财政的本质是（）

A.一种生产关系

B.一种交换关系

C.一种分配关系

D.一种消费关系

运动安全地点并经吹扫处理用火分析合格的容器、管线动火属于三级动火。

对烧结料进行预热的作用是什么？目前常用的几种预热方法是什么？