问答题 设计任务：请阅读下面学生信息和语言素材，设计 20 分钟的阅读教学方案。教案没有固定格式，但须包含下列要点：
~ teaching objectives
~ teaching contents
~ key and difficult points
~ major steps and time allocation
~ activities and justifications
教学时间：20 分钟
学生概况：某城镇普通高中一年级第一学期学生，班级人数 40 人。多数学生已经达到《普通高中英语课程标准(实验)》五级水平。学生课堂参与积极性一般。
语言素材：
The Life of Mark Twain
Often the lives of writers resemble the lives of the characters they create. Mark Twain,who wrote The Adventures of Huckleberry Finn and The Adventures of Tom Sawyer, was no exception. To start with, the author's name, Mark Twain, is itself an invention, or "pen name" . Twain's real name was Samuel Clemens.
"Mark Twain" , which means "watermark two" , was a call used by sailors on the Mississippi to warn shipmates that they were coming into shallow water.
Like Huck, Mark Twain led an adventurous life. He left school early, and as an adolescent, determined to make his fortune in South America, set off from his home in Hannibal, Missouri, for New Orleans. He wanted to take a boat to the Amazon, where he thought he could get rich quickly. He arrived in New Orleans without a penny in his pocket only to find that there were no boats for South America. Forced to change his plans, he worked for several years as a pilot on a steamboat, taking passengers up and down the Mississippi, the great river which flows from the north of the US near the Canadian border, down to the Gulf of Mexico.
Later he became a journalist and began writing stories about life on the river. Twain's vivid and often amusing descriptions of life on the river quickly became popular, and established the reputation he still enjoys today as one of America's greatest writers