题干

下列关于构成细胞的化学元素种类及作用的叙述中,不正确的是(    )

A:因为C是构成有机物的骨架,所以C是构成生物体的最基本元素

B:生物界和非生物界的统一性表现在组成生物体的化学元素的种类和无机自然界相同

C:构成生物体的化学元素的重要功能之一是组成细胞中各种化合物

D:构成生物体的大量元素包括C,H,O,N,P,S,K,Ca,Mg等

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B

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    Growing up in one of the poorest communities with most crimes in Los Angeles, US, being raised by a poorly-educated single mother and attending the worst-quality public school, not many people expected much of me, so I chose to expect something of myself.

    On my 12th birthday, I bought a poster of Harvard University to hang in my room. Being at Harvard became my dream: I saw myself attending class in Sanders Theater, studying in Widener Library and eating in Annenberg Hall. Driven by this dream, I kept studying hard. I'd begin my day by asking myself these two questions: “What do I want in my life?” and “Are the things I am doing today going to get me closer to that life?”

    Asking myself the questions gave me the courage to ask over 50 Harvard, students for advice on my application essays; it gave me the energy to study just one more hour on my SATs when others were asleep; and it gave me the determination to apply for just one more scholarship when already refused many times. Moreover, reminding myself of my goal each day made it easy to say no to the same choices my friends made, because they would never get me closer to my goal. I found that even being poor could not take away my power to decide what I choose to do with my life.

    Every day I could feel myself getting closer and closer to my goal as my writing got better, my SAT score increased, and my scholarship offers started coming in. On March 31st, 2011, an email arrived from Harvard. The first word was “Congratulations!”. Tears of joy filled my eyes.

    Who you are today is the result of the decisions you made yesterday, and who you will be tomorrow will be the result of the choices you make today. Who do you want to be tomorrow?