题目内容：

Some inventions are so useful, but seem so simple, that we wonder why no one thought of them long ago. Post-it Notes, the pieces of paper that you can stick almost anywhere and then remove without leaving any sign that they are there, are an example of such an invention.

Post-it Notes were invented about twenty years ago by Art Fry, a scientist at 3M Corporation. The idea for the product came from an upsetting experience he often had while singing in his church choir. Fry used pieces of paper as bookmarks to mark the places in his book of songs, but these bookmarks were always falling out. He knew he needed a bookmark that would stay where he put it, but that he could remove without damaging the pages.

Around that time, Fry heard about a new adhesive(粘合剂) that a colleague, Dr. Spence Silver had created. This adhesive was special because it was sticky, but not too sticky. It was strong enough to hold papers together, but weak enough not to tear the paper when it was removed. Fry saw that the new adhesive could help solve his bookmark problem. One morning, Fry put some of the adhesive on the edge of a piece of paper. Just as he hoped, it made a perfect bookmark.

A short time later, Fry realized that his new invention had even more uses than being a great bookmark. He came to this realization when he wrote a note on one of his new “bookmarks” and attached it to a report he was going to give to a colleague. Soon, co-workers were asking Fry for more sample of his invention so that they could use the new type of notes themselves.

Fry and some other people at 3M believed so much in the new product that they persuaded the company to give away thousands of the sticky pieces of paper for trial use. When some salespeople at 3M went to offices and showed workers just how helpful the new type of notes could be, they immediately received many orders. As more and more people discovered how useful Post-it Notes could be, the product took off.

1.The invention of Post-it Notes showed that Art Fry _____.

A. had a lot of knowledge.    B. was very hard-working.

C. was good at creative thinking    D. loved his job in the church

2.In what way did Dr. Spence help Art Fry?

A. They worked together and often discussed science.

B. His invention of a special adhesive made Art’s invention possible.

C. He persuaded 3M Corporation to give away lots of Post-it Notes for trial use.

D. He cooperated with Art by providing the new adhesive for Art.

3.Which of the following is a possible use of Post-it Notes?

A. A note on a friend’s door.    B. An e-mail to a friend.

C. a postcard from abroad.    D. An ad in a newspaper.

4.The biggest advantage of Post-it Notes is _____.

A. it can stay anywhere and leave no sign when removed.

B. it is very cheap to use.

C. it is good to write notes on

D. it is very thin and beautiful