问题 解答题

有1~30个自然数.两人做抢数游戏,从1开始,每人每次抢一个数或者两个连续的数,谁能抢到30这个数,谁就获胜.先抢的人能获胜吗?他要怎样做才能获胜?

答案

由于从1数到30,一共是30个数,而一个人只可以抢1或2个数,由于30是3的整数倍,故先抢数者必输;

理由如下:

若对方抢1、你就抢2、3;对方若抢1、2,你就抢3.也就是说要保证,每一个回合之后,让所剩下的数的个数为3的整数倍.

这样结果会越来越少,直到剩下最后3个数,那么无论对方抢一个或两个数都会输; 

所以,必胜的策略是:第一,让对手先抢;第二,对手抢一个数你就抢两个数,对手抢两个数你就抢一个数,始终使自己抢的数是3的倍数,如三,十五,二十七,等.

选择题
阅读理解

Microsoft founder Bill Gates has opened up about being a parent,stating that 13 is an appropriate age for a child’s first cell phone.

The 57­year­old,father­of­three,revealed on The Today Show that his children Jennifer and Rory were not allowed phones until their 13th birthday and his youngest daughter Phoebe is still waiting for one.

“We’ve chosen in our family that it’s 13 where you get a phone,” the self­made billionaire explained.

He said as a result his children often return home from school complaining,“All the other kids have one.I’m the only one without one.It’s so embarrassing.”

Asked if he keeps passwords to his son and daughters’ email and Facebook accounts,Mr Gates said that he doesn’t for Jennifer,16,who he describes as “independent”.He admitted that monitoring online activity is “a very tricky issue for parents now”.

Despite their vast wealth Mr and Mrs Gates,who live in Lake Medina,have  said  they  want  to give  their children  as  normal an upbringing as possible.

It was previously reported that their youngsters have to complete household chores and are given a modest amount of pocket money.

And in 2010 Mr Gates said that he intends to give most of his $61 billion fortune away rather than hand it down.“That wouldn’t be good either for my kids or society,” he said.

Also during the Today interview with host Matt Lauer,Mr Gates,who stepped down from Microsoft in 2008 to concentrate on philanthropy,said that helping others gives him the same excitement as creating software.

“What you really feel is what you’ve achieved.If a piece of software gets out there and lots of people love it—it lets them get their work done in better ways—that’s exciting,” he explained.

小题1:Bill Gates will not let his children own a cell phone________.

A.until they reach the age of 13

B.if they don’t really need one

C.unless they do some housework

D.before they become independent小题2:Which of the following is true about Bill Gates’ children?

A.All his children now have cell phones.

B.Phoebe has her own cell phone.

C.They are not given any pocket money.

D.Jennifer can use the Internet freely.小题3:What does the underlined word “That” refer to in the text?

A.Being a parent as a billionaire.

B.Handing all his money down to his children.

C.Allowing his children to have their phones.

D.Giving away all his money to good causes.小题4:What can we learn about Bill Gates from the text?

A.He is a warm­hearted father to his children.

B.He has created a lot of software since 2008.

C.He now devotes himself to helping others

D.He cares more about money than anything else.小题5:What is the text mainly about?

A.How Bill Gates made himself a billionaire.

B.How Bill Gates deals with his money.

C.How Bill Gates managed his business.

D.How Bill Gates brings up his children.