题干

如图所示,小明用一个沿斜面的力将大箱子推进车厢,请画出箱子沿斜面向上运动时的受力示意图.(点O为箱子的重心)
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同类题1

古文阅读。
        当余之从师也,负箧曳屣,行深山巨谷中,穷冬烈风,大雪深数尺,足肤皲裂而不知。至舍,四肢僵劲不能动,媵人持汤沃灌,以衾拥覆,久而乃和。寓逆旅主人,日再食,无鲜肥滋味之享。同舍生皆被绮绣,戴珠缨宝饰之帽,腰白玉之环,左佩刀,右备容臭,煜然若神人;余则缊袍敝衣处其间,略无慕艳意。以中有足乐者,不知口体之奉不若人也。盖余之勤且艰若此。
        今诸生学太学,县官日有禀销之供,父母有裘葛之遗,无冻馁患矣;坐大厦之下而诵《诗》《书》,无奔走之劳矣;有司业、博士为之师,未有问而不告,求而不得者也;所宜有之书皆集于此,不必若余之手录,假诸人而后见也。其业有不精,德有不成者,非天质之卑,则心不若余之专耳,岂他人之过哉?
        东阳马生君则在太学已二年,流辈甚称贤。余朝京师,生以乡人子余。撰长书以为贽,辞甚畅达。与之论辨,言和而色。自谓少时用心于学甚劳。是可谓善学者矣。其将归见其亲也,余故道为学之难告之。
                                                                                                                                                                                          (选自宋濂《送东阳马生序》)

同类题2

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Dear SJ,

    Losing a best friend is never easy.

    Your problem, is not just that you miss your best friend, it is that you feel empty and lost without her friendship.

    It takes time to get over a lost, and during that time, your mind is getting used to a new way of being. This is usually a good thing, even if it feels like a bad thing.

    Now that you are on your own, you are being forced to learn to be by yourself and to rely upon your own inner voice for guidance. I am sure that this feels strange for you, but if you can hang on for a bit longer, it may work to your advantage.

    Best friends are cool, but it is important to know the difference between missing someone and being too independent upon them.

    At your age, girls do tend to stick together and having a good boyfriend may not yet be the better choice. Your friend is leaving you, her best friend, for a boyfriend. Boyfriends are completely different from best friends. The distinction is that boyfriends come and go, while girl friends often stay in your life throughout high school, and even afterwards. It is a completely different sort of bond.

    I suggest that you take advantage of this period in your life to expand your horizons. Enjoy the freedom of having no best friend for a while, and hang with the group. By the time your former best friend breaks up with her boyfriend, you will be in a completely different place, a far better place.

    And, by the way, next time you feel empty and lost, try to write about it in a diary. In several months, you will look back and read it with curiosity about yourself. “Who was I then, and what could I have been thinking?”