What is in the drug that makes you sick or dead?For example, cocaine is harmful, but what makes it harmful?
I can’t tell you all about drugs, but I can 1 you think about them in this 2 way．Your body is a very complicated machine, 3 a lot of chemical machinery, all of which is finally turned 4 it all works together．Special chemicals, which we call drugs, can affect it in many different ways．
Some drugs are 5 when your body has a problem, as with disease－causing bacteria．Then someone may give you aspirin to keep your temperature from going too 6 or some penicillin(青霉素) 7 it stops the growth of some kinds of bacteria． 8 , all drugs are really poison, 9 if you take too much, so you must always use them 10 ．
Why do some people take drugs like cocaine?For a little while they seem to make you feel better, or happier．But 11 their effects have 12 , your body has to pay an extra 13 to get back to normal．That makes you want to get 14 of the drug．
Drugs like cocaine have their special effects because they act as 15 for your nervous system．They cut off some of your nerve pathways and take away some of your senses and your 16 ．They make you want always more．And just a little too much can even 17 nerves to your heart and stop its beating
Many of us worry about the 18 around us and what pollution does to us．How about your internal environment and what goes on 19 you?You control that all by yourself in what you put into your 20 ．Most drugs are pollutants．You would not want pollutants in the air and water around you．Why would you want pollutants in your body?
Perhaps some people in the world ever write to Big Ben．They even 1 birthday presents．In fact, Big Ben is not a 2 ．It's a clock!
Big Ben is the great clock 3 up in a tower of the Parliament(议会)building．This is the building in London 4 laws are made．The people of London like to see Big Ben's four friendly faces．They like to hear the chimes(钟声) 5 15 minutes．They like to hear the bell 6 the hours．Bong! Bong! Bong!
Big Ben's story started in 1834．In that year the old Parliament building burned 7 ．Its clock tower crashed to the ground．There 8 to be a new building and a new clock．
Plans were made．They 9 it “King of Clocks, the biggest and best in the world”．So the clock had to be big．And it had to 10 very good time．
In two years the big clock was made．Five more years went by 11 the clock tower was finished．Then the four 12 for the chimes(击钟装置)were brought into the tower．And at last the giant hour bell was put in 13 ．It 14 out for the first time on July 11,1859．
This great bell had to have a name．A meeting of Parliament was called to pick 15 ．“This clock is the King of Clocks,” one man said．“Let's call the bell Queen of Bells．”
“Then why not Victoria?” said 16 ．The talk about names went 1 ．Then Benjamin Hall got up to speak．He was a big man that others liked．By this time they were all 18 ．Someone shouted, “Why not call it Big Ben and be done 19 it?
Everybody laughed, and the meeting 20 ．But from then on, Big Ben was not just the bell but the whole clock．
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