在CAD中倒直角的命令是chA

CHA于哪年成立，总部设在哪里（）。

A:1979年河北保定 B:1989年河北保定 C:1979年北京 D:1989年北京

Science and new technology have made such rapid progress in agriculture that modern machines can do almost all farm work, and therefore have made it possible for farmers to pro- duce more food on the same amount of land. When people live in plenty, vegetables and fruits are becoming more and more popular. As a result more and more vegetables and fruits are in greater need.
Can orchard workers harvest fruits with machines as farmers to crops Yes, they can. Scientists have already invented many different fruit-harvesting machines. Now, let’s take cherry picking machine for example. The cherry-picking machine first shakes a cherry tree, then catches cherries in heavy sheets and pushes the fruit along belts. The cherries are then dropped into huge containers of water, in which they are washed clean, and look fresh and pretty when they are placed into plastic boxes which come along the belt one after another. All this work is finished within three minutes. In this way two orchard workers are able to fulfil the harvesting work of a cherry orchard within two days which was done by over one hundred workers for two weeks.
Another new machine that picks tomatoes has just been invented, First it cuts the vines below the soil. Then both the vines and the fruit are pulled into the machine which separates the tomatoes from the vines and finally returns the vines to the field.
It is believed that it will soon be possible for powerful wind machines to blow oranges off trees. New machines that are now being tested will 1Sick apples, peaches, pears and straw- berries. It is also believed that with the development of science and new technology, farm working conditions will be greatly improved, that more and more work will be done by machines instead of men and that people’s living standard will be greatly improved in the future.
Before the cherry-picking machine was invented, a present orchard worker’s one day’s work is equal to amount of work done by ______.

A:three hundred and fifty farmers a day B:one hundred farmers two weeks C:two hundred farmers two weeks D:thousands of farmers a day

Science and new technology have made such rapid progress in agriculture that modern machines can do almost all farm work, and therefore have made it possible for farmers to pro- duce more food on the same amount of land. When people live in plenty, vegetables and fruits are becoming more and more popular. As a result more and more vegetables and fruits are in greater need.
Can orchard workers harvest fruits with machines as farmers to crops Yes, they can. Scientists have already invented many different fruit-harvesting machines. Now, let’s take cherry picking machine for example. The cherry-picking machine first shakes a cherry tree, then catches cherries in heavy sheets and pushes the fruit along belts. The cherries are then dropped into huge containers of water, in which they are washed clean, and look fresh and pretty when they are placed into plastic boxes which come along the belt one after another. All this work is finished within three minutes. In this way two orchard workers are able to fulfil the harvesting work of a cherry orchard within two days which was done by over one hundred workers for two weeks.
Another new machine that picks tomatoes has just been invented, First it cuts the vines below the soil. Then both the vines and the fruit are pulled into the machine which separates the tomatoes from the vines and finally returns the vines to the field.
It is believed that it will soon be possible for powerful wind machines to blow oranges off trees. New machines that are now being tested will 1Sick apples, peaches, pears and straw- berries. It is also believed that with the development of science and new technology, farm working conditions will be greatly improved, that more and more work will be done by machines instead of men and that people’s living standard will be greatly improved in the future.

A:three hundred and fifty farmers a day B:one hundred farmers two weeks C:two hundred farmers two weeks D:thousands of farmers a day

What point is the author making by stating that farmers could carry nearly all their tools on their backs ( )

A:Farmers had few tools before the agricultural revolutions. B:Americans were traditionally self-reliant. C:Life on the farm was extremely difficult. D:New tools were designed to the portable.

下列句子中加粗的字注音正确的一项是（）
我差不多十年没有到过上海了。今年到上海出差，看到浦东参差的高楼，我感到今昔的上海差别真大啊!
 

A:cha， cha，ci，cha B:cha，chai，cha，cha C:cha， chai， ci， cha D:cha， chai， ci， cha

下列句子中加粗的字注音正确的一项是（）
我差不多十年没有到过上海了。今年到上海出差，看到浦东参差的高楼，我感到今昔的上海差别真大啊!
 

A:cha， cha，ci，cha B:cha，chai，cha，cha C:cha， chai， ci， cha D:cha， chai， ci， cha

下列句子中加粗的字注音正确的一项是（）
我差不多十年没有到过上海了。今年到上海出差，看到浦东参差的高楼，我感到今昔的上海差别真大啊!
 

A:cha， cha，ci，cha B:cha，chai，cha，cha C:cha， chai， ci， cha D:cha， chai， ci， cha