19. In an English class, a teacher took a very big bottle and put a few big stones into it. He asked the students, "Is the bottle full?"
They all answered, "Yes!"
The teacher then put some small stones into the bottle. The small stones were between the big stones. He then asked, "Is it full now?"
Some students gave no answer, but most answered, "Yes!"
The teacher then started to put some sand into the bottle. For the third time, the teacher asked, "Is it full?"
Now most students gave no answer, but some still answered, "Yes!"
Then the teacher poured a cup of water into the bottle, "What does it tell us?" asked the teacher.
One smart student answered, "No matter how busy you are, you can always find time to do some more thing."
"No," said the teacher. "If you don't put the big stones into the bottle first, you can never get them in. The big stones are the most important things in your life. If you fill your life with small things like small stones, sand and water, you'll never have the time for the most important things. "
1. What subject did the teacher teach? (不超过5个词)
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2. What does the teacher compare the big stones to? (不超过10个词)
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3. What's the main idea of the passage? (不超过15个词)
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