12. Needless to say, wasting will cause some problems. As a matter of fact, our country is in the situation where many kinds of resource are lack. If we go on wasting in our daily life, the nature will teach lessons to us in return. What’s worse, if I can speak frankly, we will make our human beings in corner. （环保）
13. Is internet good or bad for people? Students don’t see eye to eye on this issue. Some students are strongly against. Firstly， the contents of the internet are not always suitable. Secondly, it is bad for health if one uses the internet excessively. What’s worse, some students devote themselves to playing internet games but ignore their studies. （网络）
