题干

图是函数y=Asin(ωx+φ)(x∈R)在区间 [π
6
π
5
6
]
上的图象,为了得到这个函数的图象,只要将y=sinx(x∈R)的图象上所有的点(   )

A:向左平移 π3 个单位长度,再把所得各点的横坐标缩短到原来的 12 倍,纵坐标不变

B:向左平移 π3 个单位长度,再把所得各点的横坐标伸长到原来的2倍,纵坐标不变

C:向左平移 π6 个单位长度,再把所得各点的横坐标缩短到原来的 12 倍,纵坐标不变

D:向左平移 π6 个单位长度,再把所得各点的横坐标伸长到原来的2倍,纵坐标不变

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答案(点此获取答案解析)

A

同类题4

阅读下面的文言文,完成小题。      【甲】一屠晚归,担中肉尽,止有剩骨。途中两狼,缀行甚远。屠惧,投以骨。一狼得骨止,一狼仍从。复投之,后狼止而前狼又至。骨已尽矣,而两狼之并驱如故。
       屠大窘,恐前后受其敌。顾野有麦场,场主积薪其中,苫蔽成丘。屠乃奔倚其下,弛担持刀。狼不敢前,眈眈相向。
       少时,一狼径去,其一犬坐于前。久之,目似瞑,意暇甚。屠暴起,以刀劈狼首,又数刀毙之。方欲行,转视积薪后,一狼洞其中,意将隧入以攻其后也。身已半入,止露尻尾。屠自后断其股,亦毙之。乃悟前狼假寐,盖以诱敌。
       狼亦黠矣,而顷刻两毙,禽兽之变诈几何哉?止增笑耳。
      【乙】两牧竖①入山至狼穴,穴中有小狼二。谋分捉之,各登一树,相去数十步。少顷,大狼至,入穴失子,意甚仓皇。竖于树上扭小狼蹄、耳,故令嗥;大狼闻声仰视,怒奔树下,号且爬抓。其一竖又在彼树致小狼鸣急。狼闻声四顾,始望见之;乃舍此趋彼,跑②号如前状。前树又鸣,又转奔之。口无停声,足无停趾,数十往复,奔渐迟,声渐弱;既而奄奄③僵卧,久之不动。竖下视之,气已绝矣!
(选自《聊斋志异•牧竖》)
【注释】①牧竖:牧童。竖,童仆。  ②跑:兽类用足扒土。同“刨”。  ③奄奄:气息微弱的样子。

同类题5

阅读下面的短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。

    I lost my sight when I was four years old by falling off a box car in a freight(货运) yard in Atlantic City and landing on my head. Now I am thirty-two. I can slightly 1 the brightness of sunshine and what color red is. It would be wonderful to see again, but 2 can do strange things to people.

    It 3 to me the other day that I might not have come to love life as I do if I hadn't been 4. I believe in life now. I am not so sure that I would have believed in it so 5, otherwise. I don't mean that I would prefer to go without my 6. I simply mean that the loss of them made me 7 the more what I had left.

    Life, I believe, asks a continuous series of 8 to reality. The more readily a person is able to make these adjustments, the more 9 his own private world becomes. The adjustment is never easy. The hardest 10 I had to learn was to believe in myself. That was 11, If I hadn't been able to do that, I would have 12 and become a chair rocker on the front porch(门廊) for the rest of my life.

    It took me years to discover and 13 this believe. It had to start with the most elementary things. Once a man gave me an indoor baseball. I thought he was 14 at me and I was hurt. "I can't use this," I said. "15 it with you," he urged me, "and roll it around." The words stuck in my head. "Roll it around!" By rolling the ball I could hear 16 it went. This gave me an idea how to achieve a goal I had thought 17: playing baseball. At Philadelphia's Overbrook School for the Blind I invented a successful variation of 18. We called it ground ball.

    All my life I have set ahead of me a series of goals and then tried to reach them, one at a time. I had to learn my 19. It was no good to try for something I knew at the start was wildly out of reach because that only invited the bitterness of 20. I would fail sometimes anyway but on average I made progress.