已知点P关于x轴的对称点是P₁，点P₁关于原点O的对称点是P₂，点P₂的坐标为（3，4），则点P的坐标是（　　）

    “USA? Britain? Which country is____(good) to study in?” We often hear such discussion. As China opens its door, it is a dream for many Chinese students to study abroad. They want to learn about the outside world.

    It's true that studying abroad can help students develop____(they). Their foreign language skills will____ (improve) and it may be easier to find jobs.

    But there are problems____ should be considered. Language is the first. Students must spend a lot of time____ (learn) another language.

    Students must also learn____ (live) without parents' care and deal with all kinds of things they didn't have to do before, like looking after themselves. There are ____ (report) about Chinese students abroad running into an ocean of difficulties____ giving up in the end. When they have to take care ____ themselves, it is hard for students to study well.

    Finally, studying abroad brings a heavy burden to the family. For most Chinese parents, the cost of studying abroad____ (be) very high. But is it worth it?

依次填入下面一段文字横线处的语句，衔接最恰当的一组是（    ）

    据悉，欧洲议会已经正式向委员会提出议案，拟设立一套全面的法律来界定“人工智能”所带来的责任以及道德问题。      ，       ，       。       ，      ，       。怎么样，你有没有担心会因此失业呢？对于机器人的开放研究，是支持还是反对呢？

①而随着“人工智能”的普及，机器人取代人类的趋势必定会影响到就业市场

②在个别国家，例如比利时，机器人甚至已经替代人类

③“人工智能”已经广泛地运用到了我们的生活中

④肩负起了照顾老年人和痴呆症患者的工作

⑤从自动驾驶汽车，到畜牧业的机械化作业

⑥再到医疗领域的机器人应用

两个____的梯形可以拼成一个____。梯形的上底和下底的和等于____，梯形的高等于____，每个梯形的面积等于拼成的____的面积的一半，用字母公式表示是____。