以下关于本票和汇票特点的描述错误的是( )。A．依靠发行公司的信誉 B．收益率低于

所有的三角形都是轴对称图形．______．

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项，选项中有两项为多余选项。

Secret codes (密码)keep messages private。Banks, companies, and government agencies use secret codes in doing business, especially when information is sent by computer.

People have used secret codes for thousands of years. 36 Code breaking never lags(落后) far behind code making. The science of creating and reading coded messages is called cryptography.

There are three main types of cryptography. 37 For example, the first letters of “My elephant eats too many eels” Spell out the hidden message “Meet me.”  

38 You might represent each letter with a number, For example, Let’s number the letters of the alphabet, in order, from 1 to 26. If we substitute a number for each letter, the message “Meet me” would read “13 5 20 13 5.”

A code uses symbols to replace words, phrases, or sentences. To read the message of a real code, you must have a code book. 39 For example, ”bridge“ might stand for “meet” and “out” might stand for “me.” The message “bridge out” would actually mean “Meet me.” 40 However, it is also hard to keep a code book secret for long. So codes must be changed frequently.

38（）

A. It is very hard to break a code without the code book.

B. In any language, some letters are used more than others.

C. Only people who know the keyword can read the message.

D. As long as there have been codes, people have tried to break them.

E. You can hide a message by having the first letters of each word spell it out.

F. With a code book, you might write down words that would stand for other words.

G. Another way to hide a message is to use symbols to stand for specific letters of the alphabet.

“差之毫厘，谬以千里”就是因为有一个时间放大效应。所以，生涯选择需要（）

A、非常慎重地执行

B、与时俱进

C、最好进行长远考虑

D、要随机应变根据情况调整

下列各项中，属于或有事项的有( )。

A．对外提供担保

B．未来经营亏损事项

C．已贴现商业承兑汇票

D．变成亏损合同的待执行合同

E．已对外公告且有详细正式计划的重组

金刚石晶体的结合类型是典型的（）晶体，它有（）支格波。