B

Dear Tom,

    Thanks for your letter. Do you want to know about my evening? Well, I usually get home from work at 6:00 p.m. I cook dinner for my family—my parents, my sister, and my brother. After dinner I usually watch TV, play computer games or play chess. I like playing chess because my father works in a chess club. I take a shower at around nine o'clock and then go to bed at around nine thirty. Sometimes I read some books because I can learn something about my work. How about your evening? Write to me soon, please.

Best wishes,

Victor

过度包装即浪费又污染环境，据测算，如果全国每年减少10%的过度包装纸用量，那么可减排二氧化碳3120000吨，把数3120000用科学记数法表示为（   ）