问题 填空题

用适当的化学用 语填空:

(1)2个氧分子:                     (2) 镁离子:         

(3)氧化钙中钙元素显+2价:          (4)常见的钾肥:      (任写一种)。

答案

(1)2O2  (2)Mg2+   (3)    (4)K2SO4

化学符号是学习化学的基础,是初中化学中的重中之重。元素符号前面的数字表示几个该分子/原子/离子,元素符号正上方的数字表示该元素的化合价,元素符号右上角的数字表示该离子所带的电荷数。

阅读理解

Have you ever wanted to travel back in time? What about traveling into the future? There’s an easy way to do it. One way you can make a time travel journey is by writing a letter to your future self to be opened in the future. To your future self, the letter will be a visit from the past.

What can be gained by writing a letter to yourself? Depends on how good your letter is. You have the chance to say something to your future self. What would you want to communicate? You’ll be able to talk to yourself 5,10,15 years down the road. There may be instructions for your future self, or you may have goals that you will want to check up on.

There are a lot of things you could include in your letter or letters to yourself. The more you include, the better the letter will be to you. Be creative with what you put in your letter. Include a picture of yourself or family to show the period from which the letter came.

You can store your letter in many different ways. You can give your letter to a friend or family member to keep and mail to you. If you can get others to take part, have them write letters to themselves as well and ask someone to be the letter holder until it’s time to send the letters. You can also use a service online to store your letter and e-mail it to you.

小题1:How can you travel into the future?

A.By traveling back in time.

B.By paying a visit to the future

C.By opening a letter from the past.

D.By writing a letter to your future self.小题2:If you want to gain more in the future, you should_________.

A.have the chance to say something to your future self

B.talk to yourself 5, 10, 15 years down the road

C.write more about instructions for your future self

D.include as many things as possible in your letter小题3:Why do you put a picture in your letter?

A.To check up on your goals.

B.To share your feelings with your family.

C.To show the time when the letter was written.

D.To find out your thoughts and feelings now.

选择题