The Father of JD Printing

    About twenty years ago, the surgeons at the Wilford Hull medical center working to separate a pair of conjoined(连体的) twins thought that only one would be able to walk after the operation. After a model of the girls' bone structure was {#blank#}1{#/blank#} using 3D printing, however, they found a shared upper leg bone to be bigger than expected and split it successfully, {#blank#}2{#/blank#} in both twins being able to walk. Now eighty and still working as chief technology officer of 3D Systems. Chuck Hull is enjoying some minor {#blank#}3{#/blank#} 31 years after he first printed a small black eye-wash cup using a new method of manufacturing known as 3D printing.

    At the time, he was working for a company that used UV light to put thin layers of plastic coats on tabletops and {#blank#}4{#/blank#}. He had an idea that if he could place thousands of thin layers of plastic on top of each other and then cut their shape using light, he would be able to form three dimensional objects. After a year, he {#blank#}5{#/blank#} a system where light was shone into a bottle of photopolymer – a material which changes from liquid to plastic-like solid when light shines on it – and traces the shape of one level of the object. Subsequent layers are then printed until it is {#blank#}6{#/blank#}.

    After patenting the invention, he set up 3D Systems, {#blank#}7{#/blank#} getting $6m (£3.5m) from a Canadian investor. The first {#blank#}8{#/blank#} product came out in 1988 and proved a hit among car manufacturers, in the aerospace sector and for companies designing medical equipment. The possibilities appear endless – from home-printed food and medicine to {#blank#}9{#/blank#} that pictures of objects be able to be taken in shops and then recreated using plans downloaded from the Internet Although deliberate in his responses, there is one moment when the {#blank#}10{#/blank#} spoken Chuck Hull tells of his surprise about what exactly his creation was capable of achieving.

    Thank you for choosing me as the best{#blank#}1{#/blank#}. In our school, I'm really happy to share with you how passionate I am about sports and what I do to{#blank#}2{#/blank#}. I'm a big{#blank#}3{#/blank#}of many sports, including basketball, football and gymnastics. I love to watch these events on TV at the weekend. I also{#blank#}4{#/blank#}regularly, too. In the morning. I often {#blank#}5{#/blank#}on the running{#blank#}6{#/blank#}for about half an hour. I don't run too fast or for too long so that I have enough{#blank#}7{#/blank#}for the day. In the afternoon, I usually play football or basketball. I'm on the school football team. The training is always {#blank#}8{#/blank#}, but we all do our best, since we all want to{#blank#}9{#/blank#}on the team when playing against other schools. Believe it or not, we also occasionally do yoga in the{#blank#}10{#/blank#}! It helps relax our muscles and focus our minds. If you want to become fit and healthy, my advice is to try different sports and activities to see which one you enjoy the most.

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.