A teacher takes a very big bottle and puts a few big stones   into it. He asks the students, "Is the bottle full?" They all answer, "Yes!" The teacher then puts some small stones into the bottle. The small stones are between the big stones. He then asks, "Is it full now?" Some students give no answer, but most answer, "Yes!" The teacher then starts to put some sand   into the bottle. For the third time, the teacher asks, "Is it full?" Now most students give no answer, but some still answer, "Yes!" Then the teacher pours   a cup of water into the bottle. "What does it tell us?" asks the teacher. One clever student answer, "No matter   how busy you are, you can always find time to do some more things." "No," says the teacher. "If you don't put the big stones into the bottle first, you can never get _ in. The big stones are the important things in your life. If you fill your life with small things like the small stones, sand and water, you'll never have the time for the important things." What is the main   idea of the article?
We should use our time to do some more things. We should try to ask the teachers more questions. We should not put sand or water into our life. We should try to find the important things in our life.