题目内容：
Flies (苍蝇) usually live in the dirty places.Let’s look at a fly, and see where it 1 . First, it flies out of the window, 2 it stands on 3 dirty things in the street, and then it flies back to the house and walks over your 4 .
When a fly walks on the dirty things in the street, its 5 have got some germs 6 them. When the fly walks on your food with its dirty feet, it 7 the germs on your food.
What can you 8 this?
First, we learn that we mustn’t leave dirty things in the street or on the ground near 9 . Second, we learn that all food must be covered so that flies may not 1 it. Third, we learn that flies often carry germs and we must kill them as soon as we see them.
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