题干

给出下列命题:
①△ABC中角A,B,C的对边分别是a,b,c,若a>b,则cosA<cosB,cos2A<cos2B;
②a,b∈R,若a>b,则a3>b3
③若a<b,则
b
a
b
+
x
a
+
x
④设等差数列{an}的前n项和为Sn,若S2016﹣S1=1,则S2017>1.
其中正确命题的序号是____
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答案(点此获取答案解析)

①②④

同类题1

任务型阅读

    Courage is the ability to be brave in different situations in our life. Here and there, now and then, everyone needs courage to do something well. Courage may make you confident of your success. If you have courage, you will not show fear in face of anything difficult or dangerous. With courage, you may look at someone in the eye who you have wronged (冤枉) and say “I am sorry”, you may keep smiling even if you are seriously ill and know you are at the end of your life.

    How can we build up our courage?

·Believe you will be successful.

    Take chances and know that you have your own talents. Besides, your family and friends are always there for you.

·Exercise your courage.

    It can be compared to a muscle (肌肉). The more we use courage, the greater it gets.

·Know that giving up is not a choice.

    It's much easier to give up. But it takes courage to say or do what you think is right, even when other people think you are wrong.

·Read inspiring stories of brave people.

    Abraham Lincoln is one of the people who you may think of.

阅读以上信息,用恰当的词完成下面的短文,每空一词。

    Courage is the ability to be brave in different situations. It is important to everyone. With courage, you will feel confident of your success; with courage, you won't be____of anything difficult or dangerous; with courage, you may look at someone you have wronged in the eye and say sorry to him or her; with courage, you may keep smiling even if you are seriously ill.

    Here are some useful ____ to build up our courage.

    First, believe that you'll____. Take chances and know that you have your own talents.

    Second, exercise your courage. It's just like the muscle. The more we use courage, the ____ we will get.

    Third, don't____to give up although it's much easier to do so, and you need courage to say or do what you think is right, even when others think you are wrong.

    Finally, read inspiring stories of brave people. Abraham Lincoln is such a kind of person.

同类题4

阅读短文,回答问题。

    ①故乡是近海县份,八月正是台风季节。母亲称之为“风水忌”。桂花一开放,母亲就开始担心了,“可别做风水啊。”(就是台风来的意思。)她担心的第一是将收成的稻谷,第二就是将收成的桂花。桂花也像桃梅李果,也有收成呢。母亲每天都要在前后院子走一遭,嘴里念着,“只要不做风水,我可以收几大箩,送一斗给胡宅老爷爷,一斗给毛宅二婶婆,他们两家糕饼做得多”。原来桂花是糕饼的香料。桂花开得最茂盛时,不说香闻十里,至少前后左右十几家邻居,没有不浸在桂花香里的。桂花成熟时,就应当“摇”,摇下来的桂花,朵朵完整、新鲜,如任它开过谢落在泥土里,尤其是被风雨吹落,那就湿漉漉的,香味差太多了。

    ②“摇桂花”对于我是件大事,所以老是盯着母亲问:“妈,怎么还不摇桂花嘛?”母亲说:“还早呢,没开足,摇不下来的。”可是母亲一看天空阴云密布,云脚长毛,就知道要“做风水”了,赶紧吩咐长工提前“摇桂花”,这下,我可乐了。帮着在桂花树下铺篾簟,帮着抱住桂花树使劲地摇,桂花纷纷落下来,落得我们满头满身,我就喊:“啊!真像下雨,好香的雨啊。”母亲洗净双手,撮一撮桂花放在水晶盘中,送到佛堂供佛。父亲点上檀香,炉烟袅袅,两种香混和在一起,佛堂就像神仙世界。于是父亲诗兴发了,实时口占一绝:“细细香风淡淡烟,竞收桂子庆丰年。儿童解得摇花乐,花雨缤纷入梦甜。”诗虽不见得高明,但在我心目中,父亲确实是才高八斗,出口成诗呢。

    ③桂花摇落以后,全家动员,拣去小枝小叶,铺开在簟子里,晒上好几天太阳,晒干了,收在铁罐子里,和在茶叶中泡茶、做桂花卤,过年时做糕饼。全年,整个村庄,都沉浸在桂花香中。

    ④念中学时到了杭州,杭州有一处名胜满觉垄,一座小小山坞,全是桂花,花开时那才是香闻十里。我们秋季远足,一定去满觉垄赏桂花。“赏花”是借口,主要的是饱餐“桂花栗子羹”。因满觉垄除桂花以外,还有栗子。花季栗子正成熟,软软的新剥栗子,和着西湖白莲藕粉一起煮,面上撒几朵桂花,那股子雅淡清香是无论如何没有字眼形容的。即使不撒桂花也一样清香,因为栗子长在桂花丛中,本身就带有桂花香。

    ⑤我们边走边摇,桂花飘落如雨,地上不见泥土,铺满桂花,踩在花上软绵绵的,心中有点不忍。这大概就是母亲说的“金沙铺地,西方极乐世界”吧。母亲一生辛劳,无怨无艾,就是因为她心中有一个金沙铺地、玻璃琉璃的西方极乐世界。

    ⑥我回家时,总捧一大袋桂花回来给母亲,可是母亲常常说:“杭州的桂花再香,还是比不得家乡旧宅院子里的金桂。”

    ⑦于是我也想起了在故乡童年时代的“摇花乐”,和那阵阵的桂花雨。

 (选自琦君散文集《桂花雨》)