题干

设长方体的长、宽、高分别为2a、a、a,其顶点都在一个球面上,则该球的表面积为(  )

A:3πa2

B:6πa2

C:12πa2

D:24πa2

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答案(点此获取答案解析)

B

同类题1

阅读理解

    A man walked into a small Irish pub and ordered three beers. Bartender was surprised, but he served that man three beers. One hour later the man ordered three beers again. The very next day that man ordered three beers again and drank quietly at a table. This repeated several times and shortly after the people of the town were whispering about the man, who was ordering three beers at once.

    A couple of weeks later, the bartender decided to clear this out and inquired: “I do not want to pry, but could you explain, why do you order three beers all the time?” The man replied: “It seems strange, isn't it? You see, my two brothers live abroad at the moment, one – in France and another – in Italy. We have made an agreement, that every time we go to pub each of us will order extra two beers and it will help keeping up the family bond”.

    Soon all the town have heard about the man's answer and liked it a lot. The man became a local celebrity. Residents of the town were telling this story to newcomers or tourists and even invited them to that pub to look at Three Beer Man.

    However, one day the man came to pub and ordered only two beers, not three as usual. The bartender served him with bad feeling. All that evening the man ordered and drank only two beers. The very next day all the town was talking about this news, some people pray for the soul of one of the brothers, others quietly grieve.

    When the man came to pub the next time and ordered two beers again, the bartender asked him: “I would like to offer condolences to you, due to the death of your dear brother”. The man considered this for a moment and then replied: “Oh, you are probably surprised that I order only two beers now? Well, my two brothers are alive and well. It's just because of my decision. I promised myself to give up drinking.”

同类题3

阅读下面的文章,完成下列小题。

细水长流

蓝雪冰儿

    ①父亲说,以前有个算命先生说过,他是个苦命的娃。也的确,父亲十二岁丧父,不得不辍学到石灰窑工作,一干就是一辈子。

    ②后来,有人说,老刘命好,三个闺女乖巧孝顺;也有人说,老刘命好,夫妻俩没红过脸,恩爱有加;还有人说,老刘命好,从来不跟人闹意见。父亲乐呵呵地说,细水长流嘛。别人不懂父亲这话是什么意思,摸着脑瓜皮说,老刘可真逗,说你命好,你还不乐意咋的?是啊,别人觉得,细水长流和命好放在一起,这是哪跟哪啊?但我最明白,父亲的意思是说,人不要太计较利益得失,水长流,情才会长在。

    ③初为人妻,继为人母,我也喜欢把“细水长流”挂在嘴上,当然,我收获的也是幸福和快乐。但是,今年夏天,父亲的“细水长流”刚一出口,就被母亲一句话给噎回去了。

    ④这个夏天,老天爷太吝啬了,一场痛快淋漓的大雨也不下,弄得棒子苗干渴得黄了叶子,打了蔫。视地如命的母亲看着很多人家都浇了地,心急如焚。可是,我们家的地和左右两家的紧挨着,根本修不出渠来。再说,那两家都到城里去住了,平时见不到人。

    ⑤当管理水渠的人告诉母亲可以去浇地时,母亲要父亲别去上班。父亲得令而行,两人不顾炎炎烈日,在棒子地里穿梭,割伤了脸,衣服都湿透了。最终用三个小时,浇了三家的地。中午,我赶回娘家,替父母准备好午饭。母亲向来身体不好,回到家,已经没有了说话的力气,一个劲擦汗;一向强壮的父亲一屁股坐在椅子上,喘着粗气。我埋怨他们,这么大的岁数了,别把地看得比命还重要,就是旱死了,不就一年没收成吗?母亲一听,跟我急了,庄稼人能眼看着种下的庄稼死在地里啊?我不敢再接话,闷着头把午饭端上桌。母亲便自言自语,三个小时,差点把命搭进去,不知道那两家知不知情。父亲说,干了就啥也别说,细水长流。母亲吼道,水都干了,还流啥?父亲一向害怕母亲,见母亲发脾气了,连一口粗气都不敢出。

    ⑥傍晚,母亲又跟父亲唠叨开了,按理说,他们没出力,总该给点钱吧!父亲说,也不是人家让咱们浇的,爱出不出吧。这次父亲没敢说出细水长流这句话,但还是那个意思。母亲没有像中午那样发火,但心里还是不高兴。

    ⑦晚饭后,我跟父亲唠嗑,父亲说,这人啊,愿意活得累呢,就会累;愿意活得轻松呢,就会轻松。我说,是啊,细水长流。父亲笑笑说,可是,你妈有的时候,就是不明白这个理。我说,妈活得比你累。父亲说,所以,我愿意什么事都让着她。再说了,夫妻之间也是一样,不能啥都计较,还是那句话,细水长流。父亲说完,嘿嘿笑了几声,好像在女儿面前掩饰对老伴的体贴。

    ⑧我再次回到娘家,刚进门母亲就急切地对我说,丫头,还是你爸说得对,真的是细水长流。原来,前几天,左右两户人家赶回来浇地,一看地早就浇了,便把水费给了母亲,还特意拎来了他们从城里带来的新鲜水果,表示感谢。母亲一边给我拿水果,一边说,你也要记住啊,这人啊,可不能太计较。

    ⑨我瞧了一眼父亲,窗外一缕阳光正好照在他满是皱纹的脸上。

(选文有删改)