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Pre-activity: In this section, you need to read the following text and then answer the five questions.


How to Make Invisible Ink
Goal
To make invisible ink that your friend can read easily but that will be invisible to others.
Materials
One lemon
An old-fashioned pen with steel nib, or a fountain pen
Paper
Reading light
What to do
1. Before beginning, carefully cut a ripe lemon in two. Squeeze the juice of the lemon into a juicer.
2. Use a funnel to slowly pour the liquid into a small container.
3. Next, select an old-fashioned pen with a steel nib, or a fountain pen.
4. Dip the pen into the liquid and write down your message neatly on a blank sheet of paper. Make sure you write legibly.
5. Place it nearby on a desk or table to dry. When your writing dries, it should be invisible.
6. Now send the message to your friend. Explain that for the message to become visible, it must be held near a reading light. It should be held near the light, but not too close. The heat from the light will make the lemon-juice writing visible.


Now, you can answer the following questions now. For the Question 1 to 4, just click the radio button before the choice you choose; for the last question, you can write down a few sentences.


1) What does this text talk about?

a.It talks about what invisible ink is 

b.It talks about how to make invisible ink 

c.It talks about the importance of the invisible ink
2) What should you do with the old-fashioned pen or the fountain pen?

a. Dip it into the lemon juice and write down the message on a blank paper. ;

b. Write down the message directly;

c. Decorate the pen

3) Why will the writing become visible when you hold it near the reading light?

a. he light is bright, so the words are visible under it. ;

b. The light makes the ink show up.;

c. The heat from the light makes the words visible. 
4) Why the paper with the invisible words couldn't be held too close to the reading light?

a. It's hard to read when you hold it too close to the light.;

b. It would be too hot if you hold the invisible words too close to the light, so thus damages the words.;

c. The light may be too bright when you hold the invisible words too close to the light, so it would be hard to read.

5) Do you think it's a good way to send message to your friend? Why or why not?