以下关于票证的核算在征管系统中哪些说法是正确的？（）A、票证的台帐可以删除后重新抽取

填入下面横线上的词语，最恰当的一项是[ ]

（1）在访问这里之后，    不说些什么___写些什么就离开，那就对不起在这里遇难的人们。

（2）____中国科技界来说，1986 年的春天，    来得比哪年都早。

A．如果   或   对于   可能

B．只要   或   对       可能

C．只要   和   对于   或许

D．如果   和   对       或许

物质A(C₁₁H₁₈)是一种不饱和烃，它广泛存在于自然界中，也是重要的有机合成中间体之一。某化学实验小组从A经反应①到⑤完成了环醚F的合成工作

该小组经过上述反应，最终除得到F1 ()外，还得到它的同分异构体，其中B、C、D、E、F、分别代表一种或多种物质。

已知：

请完成：

(1)写出由A制备环醚F1 的合成路线中C的结构简式：_______________________。

(2)①写出B的一种结构简式：____________________；

②写出由该B出发经过上述反应得到的F1的同分异构体的结构简式：____________________________。

(3)该小组完成由A到F的合成工作中，最多可得到________种环醚化合物。

在贞观诗坛的后期，出现了一位重要诗人（），形成一种诗风“（）”。

It was a village in India. The people were poor. However, they were not unhappy. After all, their forefathers had lived in the same way for centuries.

Then one day. Some visitors from another city arrived. They told the villagers there were some people elsewhere who liked to eat frog’ s legs. However, they did not have enough frogs of their own, and so they wanted to buy frogs from other place.

This seemed like money for nothing. There were millions of frogs in the fields around, and they were no use to the villagers. All they had to do was to catch them. Agreement was reached, and the children were sent into the fields to catch frogs. Every week a truck arrived to collect the catch and hand over the money. For the first time, the people were able to dream of a better future. But the dream didn’t last long.

The change was hardly noticed at first, but it seemed as if the crops were not doing so well. More worrying was that the children fell ill more often, and, there seemed to be more insects around lately.

The villagers decided that they couldn’ t just wait to see the crops failing and the children get-ting weak. They would have to use the money earned to buy pesticides (杀虫剂) and medicines. Soon there was no money left.

Then the people realized what was happening. It was the frog. They hadn’ t been useless. They-had been doing an important job—eating insects. Now with so many frogs killed, the insects were increasing more rapidly. They were damaging the crops and spreading diseases.

Now, the people are still poor. But in the evenings they sit in the village square and listen to sounds of insects and frogs. These sounds of the night now have a much deeper meaning.

From paragraph 1, we learn that the villagers().

A. worked very hard for centuries

B. dreamed of having a better life

C. were poor but somewhat content

D. lived a different life from their forefathers

由单选和多选组成。

该土地每年应缴纳的城镇土地使用税为( )元。

A．20000

B．40000

C．50000

D．80000