1. Many people are inclined to do one job in their lives. In their opinions, people who change their jobs frequently are superficial and tactless.

2. They believe that the only way to success is to stick to one job, for constant practice in a professional field helps make an expert.

3. But there are still many people who don’t agree. They argue that change means progress. If you are not satisfied with your present job, of course you have the right to replace it with amore challenging and better paid one.

4. Every change is a step to further success. This idea may be the reason why they change their jobs so often.

5. For my part, I think it reasonable to change your job if you have a better opportuniry. But once you have found a position where you can fully display your ability, it is advisable to settle down to it and put all your efforts into it.

6. Only in this way, can you get the true joy of achieving your goal.

7. In fact, environmental pollution is a very serious problem the whole world is facing.it ismainly caused by the waste products released from artificial substances, industrial productionand increased consumption of goods.

8. Bedsides, the use of chemical substances in agriculture also causes environmental pollution.

9. Look at the sky, you can see that dense smoke is being released from the high and big chimneys; those dirty and poisonous substances are flowing into the rivers that we use for drinking water and millions of tons of waste products are heaping around us.