题目

任务型阅读     It is said that about half of the people in China smoke. Many young boys and girls have the habit of smoking, though they are middle school students. More and more people have come to realize how serious this problem is. But they are never bored with it. Some people think it is a kind of fashion, some think it is of great fun and others think that smoking can refresh themselves（提神）. Smoking causes many illnesses. A lot of people always cough ‚              smoking. The most serious illness caused by smoking is lung cancer. At the same time下列属于可遗传的变异的是（　　） A、由于水肥充足，小麦出现穗多粒大的性状B、紫外线照射使人得皮肤癌C、在一群红眼野生型果蝇中出现了白眼果蝇D、人由于晒太阳而使皮肤变黑