题目内容

【题目】设α∈{2,1,,1,2,3},则使f(x)=xα为奇函数,且在(0,+∞)上递增的α的个数是( )

A.1 B.2 C.3 D.4

【答案】C

【解析】f(x)为奇函数,则α=1,,13

f(x)在(0,+∞)上递增,则α=,13,故选C.

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【题目】

Kids dont have to pay bills,cook dinners,or manage car polls (合伙使用汽车).Butjust like adultsthey have their share of daily demands and things that dont go smoothly.If frustrations and disappointments pile up,kids can get worried.

Its natural for all kids to worry at times,and because of personality differences,some may worry more than others.Luckily,parents can help kids manage worry and deal with everyday problems with ease.Kids who can do that develop a sense of confidence and optimism that will help them master lifes challenges,big and small.

What kids worry about is often related to the age and stage theyre at.Kids and preteens typically worry about things like grades,tests,their changing bodies,fitting in with friends,a goal they missed at the soccer game,or whether theyll make the team.They may worry about social troubles like cliques (派系,小圈子),peer (同龄人) pressure,or whether theyll be bullied (欺负),laughed at,or left out.Because theyre beginning to feel more a part of the larger world around them,preteens also may worry about world events or issues they hear about on the news or at school.Things like terrorism,war,pollution,global warming,endangered animals,and natural disasters can all become a source of worry.

【1】From the passage,we learn that________.

A.not kids but adults may get worried about something

B.the worries that kids experience vary from one to another

C.kids worry about the same issues,regardless of their age

D.preteens may not worry about fire or earthquakes

【2】What is the third paragraph mainly about?

A.Advice on removing kids worries.

B.The negative results of getting worried.

C.Why kids get worried.

D.What kids may worry about.

【3】The next paragraph might talk about________.

A.suggestions for kids to deal with worries

B.the importance of avoiding getting worried

C.different opinions on kids getting worried

D.subjects that teenagers and adults worry about

【4】The passage is most likely intended for________.

A.scientists

B.teachers

C.parents

D.doctors

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