I had neither a raincoat nor an umbrella. That’s why I ______wait until the rain stopped.
A. might       B. should      C. ought to     D. had to

We all know the meeting ______ yesterday was of ________

　 A．held ; very important　　　 B．was held; great importance

C．held ; great importance　　　　 D．being held ; very important

-- Hasn’t the secretary told you the details?

-- No. She ______ give me the details. I have already known about them.

A. can’t 　 　　　 B. needn’t 　　 C. shouldn’t 　 D. mustn’t

—Shall we go out for dinner tonight?

　 — ______ .　

A. You are right　 B. It must be funny C. That sounds great　　 D. Have a nice time

If you and your friends wish to share a secret, you can write it in code, and no one else will be able to read it. Codes are one way of writing in secrets. Ciphers(暗码) are another. In the code each word is written as a secret code or word number. In a cipher each letter is changed.

Codes and ciphers have played an important role in the history of the word. Julius Caesar, the Roman ruler who defeated almost all the countries in Europe about 2000years ago, used a cipher when he sent secret messages to his troops. During American Revolution, George Washington’s spies used a kind of code to send him information about the enemy before his military（军事的） action. In World War 2,the American “broke”, or figured out, Japan’s most important navy codes and got enough information to destroy a powerful Japanese fleet（舰队）。

Storekeepers use codes to mark their goods. The codes show how much was paid for the goods or when they were added to the stock. Businessman use codes to hide plans from their business enemies. Sometimes personal letters or diaries are written in code. Many people enjoy figuring out codes and ciphers simply as a hobby.

In the 16th century, codes and ciphers were very popular among scientists. They wrote messages to each other in code so that no one else would learn their secrets. Geronimo Gardano, an Italian astrologer（星相家）,mathematician, and doctor, invented the trellis ciphers. He took two sheets of paper and cut exactly the same holes in each one. Then he sent one sheet, which he called a trellis, to a friend and kept the other for himself. Whenever he wanted to write a message, he put his trellis, over the clean sheet of paper and wrote the secret message through the holes. Then he removed the trellis and filed the rest of the paper with words that would make sense. When his friends received it, He put his trellis over the writing and read the secret message.

Title 71.            

The word “hoon” is a term commonly used in Australian culture to ______ young people who engage in what may be thought of as dangerous driving behavior.（ ）

A. turn to　　 B. belong to　　 C. adapt to　　　 D. refer to

If you sleep short of 7 hours, you are three times _______ to catch a cold．

　 A．possible　　 　　　　　　　 B．certainly　 C．probable　 D．likely　

How we ______(获得) knowledge seems obvious.

A teacher’s ________ to education is worth great respect of the whole society because it brings benefits to the development of society.

A. devotion　 　 B. principle　　 　 C. identity　 　　　 D. guidance

You television.Why not do something more active?

　　A.always watch B.are always watching

　　C.have always watched D.have always been watching