题干

已知a,b∈R,i为虚数单位,当a+bi=i(1﹣i)时,则 −
a
+
b
i
a
b
i
=(   )

A:i

B:﹣i

C:1+i

D:1﹣i

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答案(点此获取答案解析)

A

同类题2

完成短文

    Once my mother told me a story. In Africa, when an antelope (羚羊) wakes up every morning, the first thing it thinks about is, “I must be able to run faster than the fastest lion, or I will be k____.” At the same time, a lion wakes from his dream. The first thing the lion thinks about is, “I must be able to catch the ____antelope, or I will die of hunger .” So almost at the same time, the antelope and the lion get up and start running toward the rising sun.

This is life: full of chances and challenges. Whether you are an antelope or a lion, you must go a____when the sun rises. For students, it is just the same. If we don't study hard, sooner or later, we will fall b____the other students. At first, I didn't know what the word “exam” meant. Later, I knew an exam was a kind of competition. In competitions, there are always w____ and losers. As I grew up, I got to know “competition”. In one's life, there must be competitions, so people can improve.

    Each time I saw children playing games and heard their laughter, I wished I were that age again. However, I remembered my parents' words: “You must work very hard in order to have a good f____. ” So I picked up my pen and began to study hard again.

    I was still not sure what competition really meant. One day, I was taking part in an English-speaking competition. When I went to the stage, I saw other students looking at me kindly. I s____ knew what competition was. It is not as cruel as my teacher and parents told me. In fact, competition is the opposite: it is kind and necessary.

    I learned a lot from realizing this . Now I understand better about the world. Competition is important for us all.

同类题3

阅读下文,回答相关问题。

                                                                                                                                      背影(节选)
        那年冬天,祖母死了,父亲的差使也交卸了,正是祸不单行的日子。我从北京到徐州打算跟着父亲奔丧回家。到徐州见着父亲,看见满院狼藉的东西,又想起祖母,不禁簌簌地流下眼泪①。
        ◆第一次流泪,是悲哀。作者怀着沉重的心情,从北京赶到徐州跟父亲一起奔丧,见到那“满院狼藉的东西”,触目伤怀,才不禁潸然泪下。
        丧事完毕,父亲要到南京谋事,我也要回北京念书,我们便同行。
        到南京时,有朋友约去游逛,勾留了一日;第二日上午便须渡江到浦口,下午上车北去。父亲因为事忙,本已说定不送我,叫旅馆里一个熟识的茶房   陪我同去。他再三嘱咐茶房,甚是仔细。但他终于不放心,怕茶房不妥贴;颇踌躇了一会。终于决定还是自己送我去。我再三劝他不必去;他只说:"不要紧,他们去不好!"
        我们过了江,进了车站。我买票,他忙着照看行李。行李太多了,得向脚夫行些小费才可过去。他便又忙着和他们讲定价钱;就送我上车。他给我拣定了靠车门的一张椅子。他嘱我路上小心,夜里要警醒些,不要受凉。又嘱托茶房好好照应我。
        我说道:"爸爸,你走吧。"他往车外看了看说:"我买几个橘子去。你就在此地,不要走动。"我看那边月台的栅栏外有几个卖东西的等着顾客。走到那边月台,须穿过铁道,须跳下去又爬上去。父亲是一个胖子,走过去自然要费事些。我本来要去的,他不肯,只好让他去。我看见他戴着黑布小帽,穿着黑布大马褂,深青布棉袍,蹒跚地走到铁道边,慢慢探身下去,尚不大难。可是他穿过铁道,要爬上那边月台,就不容易了。他用两手攀着上面,两脚再向上缩;他肥胖的身子向左微倾,显出努力的样子,这时我看见他的背影,我的泪很快地流下来了,我赶紧拭干了泪。怕他看见,也怕别人看见。我再向外看时,他已抱了朱红的橘子往回走了。过铁道时,他先将橘子散放在地上,自己慢慢爬下,再抱起橘子走。到这边时,我赶紧去搀他。他和我走到车上,将橘子一股脑儿放在我的皮大衣上。于是扑扑衣上的泥土,心里很轻松似的。过一会说:"我走了,到那边来信!"我望着他走出去。他走了几步,回头看见我,说:"进去吧,里边没人。"等他的背影混入来来往往的人里,再找不着了,我便进来坐下,我的眼泪又来了②。
        ◆第二次流泪,是___________________________________________________________。
        近几年来,父亲和我都是东奔西走,家中光景是一日不如一日。他只是惦记着我,惦记着我的儿子。我北来后,他写了一信给我,信中说道:"我身体平安,惟膀子疼痛厉害,举箸提笔,诸多不便,大约大去之期不远矣。"我读到此处,在晶莹的泪光中③,又看见那肥胖的、青布棉袍黑布马褂的背影。唉!我不知何时再能与他相见!
        ◆第三次落泪,是伤心。以在晶莹的泪光中再现的父亲的“背影”结篇,与开头呼应,表达了作者对年迈的父亲无限思念,凄切动人。