可用推拉注射器活塞的方法检查如图中装置的气密性．当缓慢拉活塞时，如果装置气密性良好，可观察到（　　）

过度包装既浪费资源又污染环境，据测算，如果全国每年减少十分之一的包装纸用量，那么能减少3120000吨二氧化碳的排放量，把数据3120000用科学记数法表示为（   ）

C

    In April 2004,Sharon Tirabassi got more than $10 million(一百万)by winning a lottery(彩票抽奖)．She became very rich．But just in nine years，she spent almost all the money．Now she even has to work hard to make enough money for everyday use．

    Before she won the lottery, Sharon lived in a small apartment with her three children and didn't have enough money for a car．After she won it，she was unprepared for the change to her life．She spent most of her time shopping with her friends and paid for everything．She bought a big house in the richest part of town and four cars．

    Today, Sharon lives in a rented(租来的)house on a quiet street-not far from where she started．She doesn't have the big house or the expensive cars．She goes to work by bus or by bike．

But Sharon says she's happier now than she used to be．and she lives life more fully than she did before．”When I was rich，I spent all my time shopping．But now other things are more important to me．”says Sharon．Now Sharon works hard and

often talks with her children.” I'm trying to get them to learn that they have to work for money ，” she says．