All electrical circuits fall into one of ______ classes: series circuits, parallel circuits, and series parallel circuits.

All electrical appliances aboard a vessel should be grounded to ______.

A.prevent them from falling when the vessel rolls

B.protect personnel from electrical shock

C.increase their operating efficiency

D.prevent unauthorized personnel from operating them

You will fall into the fourth stage of sleep______.

A．about 80 minutes after you fall into slumber

B．some 10 minutes after your fall into REM sleep

C．about 40 minutes after you lose consciousness

D．some 30 minutes after your brain waves slow

You will fall into the fourth stage of sleep ______.

A．about 80 minutes after you fall into slumber

B．some 10 minutes after your fall into REM sleep

C．about 40 minutes after you lose consciousness

D．some 30 minutes after your brain waves slow

You will fall into the fourth stage of sleep______.

A．about 80 minutes after you fall into slumber

B．some 10 minutes after your fall into REM sleep

C．about 40 minutes after you lose consciousness

D．some 30 minutes after your brain waves slow

Schools in England fall into two categories: One is public schools, which his maintained by local authorities and free to all children; the other is private schools or independent schools, which parents need to pay for their children's education.

A．Y

B．N

C．NG

Decision-thinking is not unlike poker—it often matters not only what you think, but also what others think you think and what you think they think you think: The mental process (过程) is similar. Naturally, this card game has often been of considerable interest to people who are, by any standards, good thinkers.

The great mathematician John yon Neumann was one of the founders of game theory. In particular, he showed that all games fall into two classes: there are what he called games of "perfect information", games like chess where the players can't hide anything or play tricks: they don't win by chance, but by means of logic and skills. Then there are games of "imperfect information", like poker, in which it is impossible to know in advance that one course of action is better than another.

One mistaken idea about business is that it can be treated as a game of perfect information. Quite the reverse, business, politics, life itself are games which we must normally play with very imperfect information. Business decision are often made with many unknown and unknowable factors(因素)which would even puzzle(困惑)best poker players. But few business people find it comfortable to admit that they are taking a chance, and many still prefer to believe that they are playing chess, not poker.

The subject discussed in this text is ______.

A．the process of reaching decisions

B．the difference between poker and chess

C．the secret of making good business plans

D．the value of information in winning games