为了探究外界条件对植物光合作用的影响，某研究小组将某品种植物长势一致的盆栽苗分成甲、乙两组，置于密闭的人工气候室中，甲组模拟自然光照，乙组提供低光照，其他培养条件相同．培养较长一段时间（T）后，测定两组植株叶片随光照强度变化的光合作用强度（即单位时间、单位叶面积吸收CO₂的量），每组做3次重复，光合作用强度随光照强度的变化趋势如图所示．

阅读理解

    Keeping pace with teachers is a fine way to study English. Teachers are experienced and their plans are systematic. But remember to work in a way that suits you. It's important to learn from past mistakes as well. Keep a notebook to make a record of the mistakes you make－it'll help you avoid making the same ones later.

    The time of life may be hard，but you're not alone. You may be busy studying，but you can show your care by calling your friends or sending short messages. Don't let your friendships die.

    It's as important to live well as it is to study well. Going to bed no later than 11：30 pm is vital. It puts you in the right mood for the next day. You needn't follow a special diet，but make sure you are eating nutritious meals each day.

    The person who plays well，studies well. Having a lot of schoolwork doesn't mean having to give up other activities. Playing basketball or having a talk with your classmates can relax yourself. Time out is not a waste of time but helps you study more efficiently.

    Besides taking the big exam，you have other choices for college. I took the independent enrollment exam held by Peking University and some other students even were preparing to study abroad. Pay attention to any relevant information you can find，whether it's from school，the news media or other sources.

一定质量理想气体经历如图所示的A→B、B→C、C→A三个变化过程，T_A=300K，气体从C→A的过程中做功为100J，同时吸热250J，已知气体的内能与温度成正比．求：

下列句子顺序排列正确的一项是（   ）
①这样的态度都是不足取的。
②因此，发展的机遇要从解决难题、克服困难中赢得，而抓住机遇也正是解决难题、克服困难的过程，机遇总是偏爱有准备的大脑。
③正像运动员到奥运赛场拼搏，既是机遇，也蕴涵着挑战，既是挑战，又孕育着机遇。
④把两者割裂开来，以为机遇就是天上掉馅饼的时运，消极等待；或以为挑战就是数不胜数的难题，唉声叹气。
⑤机遇与挑战是密不可分的，加快发展离不开机遇，也避免不开挑战。