将下列句子中的汉语部分译成英语，注意使用适当的形式。

1. David Beckham is a great British               . (足球运动员)

2. On school days, we often                our homework. (从事,忙于)

3. Working hard is of great important, but               you must do some exercise to keep fit. (同时)

4. Last weekend, we went hiking. It was tired, but               we all reached the top of the mountain. (最后)

5. My sister is going to be a student at an               in Pairs. (艺术学校)

第二次科技革命最显著的成就是(    )

A．电力的广泛应用

B．内燃机成为新的动力机

C．化学领域新材料层出不穷

D．炼钢技术的突飞猛进