激光是由____产生的，与日光、灯光相比，具有____、____、____的特性。

神经元是神经系统结构和功能的基本单位，它主要的生理功能是（　　）

补写出下列句子中的空缺部分。

①杜牧在《阿房宫赋》中写阿房宫走廊曲折、屋檐高耸的句“____，____。”

②李贺在《李凭箜篌引》中写李凭在梦中将他的绝艺教给神仙，惊动了仙界的句子是“____，____。”

③李白《春夜宴从弟桃花园序》中写大家高兴地观赏盛开的桃花，在月光下不停地传杯递盏的句子是“____，____。”

在用伏安法测未知电阻R_x时，如果缺少电流表或电压表，可以通过增加一个定值电阻R₁和开关来解决，下面的四种方案中哪一个是错误的（　　）

阅读下面短文，从每题所给的A、B、C、D四个选项中选出最佳选项。

    Do you want to become an astronaut? If you want to be one of the few people to experience the thrill of lift-off(发射), see the Earth from on high and float(漂浮) in a spacecraft, then how do you go about it?

First, you must really want to become an astronaut as it takes many years of study and work before you even begin your astronaut training. Most astronauts begin when they are between 27 and 37. Second, you need to be clever enough to attend a university to study engineering, medicine or one of the sciences. Many astronauts also learn to be pilots in their country's air force(空军). Third, astronauts come from many different countries, so they need to speak English. Then they can all talk to one another. Fourth, you must be healthy as astronaut training can be very tiring. Lastly, on a spacecraft, astronauts live and work in a very small space, so you need to get on well with people.

    Are you still interested? If so, maybe you will become one of the men or women that orbit the Earth in a spacecraft, walk in space or visit Mars. See you in space!