车削加工主要用于加工回转曲面的型腔或型腔中的()。
参考答案:回转曲面
补全对话,每空一词。
A:Betty, what kind of pet would you like to 1 ?
B: 2 do you think of cats? They are lovely and quiet.
A:They are boring, and they are too lazy. How 3 dogs? They are. 4 to people.
B:Well, dogs are too 5 to me. I don't like them at all. I think goldfish 6 interesting to take care of. And they are 7 in the room, too. We don't have to clean the room
every day.
A: That's right. But you should 8 a good fishbowl.
B:Goldfish are so colorful, and they look really 9 .
A:I hope you will 10 your pets.
1. 2. 3. 4. 5.
6. 7. 8. 9. 10.
下列各组物质的性质比较中,不正确的是[ ]
A.酸性强弱:HIO4>HBrO4>HClO4
B.原子半径大小:Na >S>O
C.碱性强弱:KOH>NaOH>LiOH
D.金属性强弱:Na >Mg>Al