一、直接引入类

1. I have a friend who... Should he...？ （通过具体事例引出争议性话题）

2. Once upon a time, there lived a man who... This story may be unbelievable, but it still has a realistic significance now. （经典童话式开头，适用于寓言或社会现象类作文）

二、现象描述类

1. Nowadays, with the development of technology... （以社会现象为切入点）

2. It is astonishing to see that... （引发读者好奇心）

三、反差对比类

1. What would our society be like if there were no...？ （假设性提问）

2. On one hand,... On the other hand,... （正反对比结构）

四、名言引用类

1. "Knowledge is power." This is the remark made by Bacon. （名人名言增强权威性）

2. "Education is not complete with graduation." （哲学观点引发思考）

这些句子可根据作文主题灵活调整，建议搭配具体事例或数据增强说服力。若需进一步优化，可结合图表、统计数据等元素丰富内容。