When Marco Polo was 17 years old, he travelled {#blank#}1{#/blank#} Europe and Asia with his father, who wanted to do trade with the Chinese. And {#blank#}2{#/blank#} they arrived in Beijing.

    Marco was amazed by how beautiful and powerful China was. He was impressed by Beijing and the Emperor's palace. He was surprised to see Chinese people using paper money in the markets because he could not understand how people could pay for food and valuable things with paper! He was also {#blank#}3{#/blank#} by the black stones people used to burn for fuel. The black stones were coal, but Marco had never seen it before.

    Not long after his return to Italy, a local war {#blank#}4{#/blank#}. During the war, he was caught by the enemy and put into prison. Another prisoner, who was an author, took {#blank#}5{#/blank#} while Marco told all his stories about China and wrote the stories in a book called The Description of the World.

    Frederick Douglass was an escaped slave in the movement that fought to end slavery in the United States. He became a{#blank#}1{#/blank#} voice in the year before the Civil War.

    A few weeks ago, the National Park Service (NPS) {#blank#}2{#/blank#} Douglass's birth and Black History Month with reopening of his home at Cedar Hill, a{#blank#}3{#/blank#}  site in Washington. D.C. The two-story house, which contains many of Douglass's personal possessions, had undergone a three-year {#blank#}4{#/blank#} . (Thanks to the NTS website, however, you don't have to live in the nation's capital to visit it. Take a tour online.)

He was born in Frederick Augustus Washington Bailey to a slave mother and a white father who never knew Douglass grew up to become the first black {#blank#}5{#/blank#} to hold a government office— as US minister and consul general (总领事)to Haiti.

    As a youth, he never went to school. Educating slaves was illegal in the South, so he{#blank#}6{#/blank#}  taught himself to read and write. At 21 years old, he escaped from his slave owner to Massachusetts and changed his last name to Douglass, to hide his identity.

    In the 1850s, Douglass was involved with the Underground Railroad, the system {#blank#}7{#/blank#} up by antislavery groups to bring runaway slaves to the North and Canada. His home in Rochester, N.Y. was near the Canadian border. It became an important station on the {#blank#}8{#/blank#} , housing as many as 11 runaway slaves at a time.

    He died in 1895. In his lifetime, Douglass {#blank#}9{#/blank#}  the end of slavery in 1865 and the adoption of the 15^th Amendment to the US Constitution (美国宪法修正案), which{#blank#}10{#/blank#} African-Americans the right to vote.

What Is a Paragraph Break?

It is one of the most important punctuation marks. A paragraph break is an indentation (缩造) or a single line space{#blank#}1{#/blank#}the division between one paragraph and the next in a body of text.

Generally, paragraph breaks serve to{#blank#}2{#/blank#}the transition from one idea to another in a stretch of text, and from one speaker to another in an exchange of dialogue.

Few readers would think of the paragraph break as a punctuation mark, but it certainly is. In ancient times there were no paragraphs. Sentences simply flowed into one another without{#blank#}3{#/blank#}.During medieval (中世纪) times, the mark evolved into the paragraph symbol and eventually became the modern-day paragraph break, which is{#blank#}4{#/blank#}now only by a line break or indentation.

Today, the paragraph break is used to give readers a break. The art of creating paragraphs is called paragraphing, the{#blank#}5{#/blank#}of dividing a text into paragraphs. Paragraphing is a kindness to your reader because it divides your thinking into manageable bites. Paragraphs that are too long{#blank#}6{#/blank#}readers with dense blocks of text to read through, while more frequent paragraphing provides readers with convenient{#blank#}7{#/blank#}points at which to take a break and relaunch themselves into thinking.

To fully understand when to insert a paragraph break, it's helpful to know that a paragraph is a group of closely related sentences that develop a central idea. Therefore, each paragraph discusses one{#blank#}8{#/blank#}topic. Also, a paragraph break is cmploycd before each new topic is introduced. In this way, the writing will flow, and readers will be able to proceed through the writing in a logical fashion instead of{#blank#}9{#/blank#}all the way to get to the last line.

Paragraphs used to be longer, but with the development of the Internet, which gives readers access to literally millions of sources of information, paragraphs have become increasingly{#blank#}10{#/blank#}. The style for many websites, for example, uses paragraphs no more than two to three sentences.