问题
单项选择题
天然砂按其产地不同，有河砂、海砂、( )等之分。
A．屑砂
B．山砂
C．矿砂
D．尘砂
答案
参考答案：B
搜题请搜索小程序“爱下问搜题”
天然砂按其产地不同，有河砂、海砂、( )等之分。
A．屑砂
B．山砂
C．矿砂
D．尘砂
参考答案：B
These days，cars are designed using computers．Let’s look at how a new car is created． First，several 16 talk about the new car and any good ideas that they have．Then they sit down at their computers and 17 many sketches．The best two or three drawings are chosen and then more detailed drawings of 18 are developed on the computer．You can change the size，shape or color of any part on the computer to see 19 the car would look and then you can choose the best design． Both the inside and the outside of the car have to be designed．Part of the inside of the car is 20 so that the designers can sit in it．They can feel if there is enough 21 inside and if they can reach 22 ．Then some cars are built-there are more than 15，000 parts of a car to 23 ． When everything is known to be 24 ，the cars are made in the factory．Again，computers are used to make sure that all the parts are 25 as they are needed．The factory usually stays open all through the night so that the car production never stops．
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