压差计是利用（）原理进行测压的。A、动力学 B、静力学 C、液柱 D、连通器

北京市地方标准DB11/419-2007《电梯安装维修作业安全规范》中规定，在底坑作业时要按下底坑停止开关，使电梯不能运行。()

All students need to have good habits (习惯): When you have good study habits, you can learn things quickly. You can also remember (记住) them easily.

Do you like to study in the living room? This is not a good place because it is usually too noisy. You need to study in a quiet place, like your bedroom. A quiet place will help you only think about one thing, and you will learn better.

Before you study, do not forget to clean your desk. A good desk light is important (重要的), too. You’ll feel tired easily if (如果) there is not enough light.

小题1:When you have good study habits, you will ________.

A．learn things quickly

B．remember things easily

C．think about one thing

D．both A and B小题2:The living room is not a good place for study because it is too ________.

A．quiet

B．noisy

C．good

D．clean小题3:You should remember to ________ before you study.

A．clean the desk

B．clean the room

C．open the door

D．open the window小题4:You’ll feel tired easily if the light is ________.

A．enough

B．good

C．bad

D．wonderful小题5:The best title (标题) for this passage is ________.

A．Study in the Bedroom

B．Good Study Habits

C．How to Study

D．Desk Light Is Important

下列实验操作中正确的是     

A．向盛有少量浓硫酸的量筒中缓慢加入一定量的水并搅拌，可得稀硫酸

B．分液操作时，分液漏斗中下层液体从下口放出，上层液体从上口倒出

C．蒸馏操作时，应将温度计水银球插入液面下

D．称量氢氧化钠固体的质量时，将称量物放在纸片上，并置于托盘天平的左盘，砝码放在托盘天平的右盘

--- Alice had nothing for breakfast this morning ,____ ?

--- No, she got up too late.

A．had she

B．hadn’t she

C．did she

D．didn’t she

文献记载钢铁是"杂炼生（生铁）缫（熟铁）为刀镰者。"此文献提到的金属冶炼技术发明于（）。

A.春秋战国时期

B.两汉时期

C.魏晋南北朝时期

D.隋唐时期