Nowadays, there exists an increasingly serious social/economic/environmental problem. ________(具体的社会问题或者现象)has increasingly become a common concern of the public. According to a survey, ________(说明这种现象的情况或者举一个例子).
There are a couple of reasons behind this problem/phenomenon. For one thing, ________(理由一); for another, ________(理由二). What is more, ________(理由三).
Based on the above discussions, I can easily forecast that more and more people will ________(作出某种反应).
Nowadays, there exists a common phenomenon：with the development of the Internet, more and more people tend to send electronic cards instead of paper ones to their friends and relatives when an important holiday comes.(具体现象)
There are a couple of reasons behind this phenomenon. For one thing, compared with the traditional cards, electronic cards are livelier and more interesting. They can give not only pictures but also sound and animations. For another, there are many websites online which offer varieties of cards to you to choose from. What is more, with the popularity of the electronic cards, less paper is used in making paper cards, which does good to our environment.(理由)
Based on the above discussions, I can easily forecast that sending greetings by using electronic cards will be accepted by more and more people.(预测前景)
例如想表达“邮递员天天准时到”，如果写成The postman comes on time every day，就不如变成双重否定，The postman never fails to come on time，就变成了亮点句，起到强调作用。
“几乎每个人对生活的态度都不同程度受到地震的影响”，写成双重否定There was hardly a man or a woman whose attitude towards life had not been affected by the earthquake.