合同法属于（）。 A.商法 B.宪法 C.刑法 D.民法

把A-E五个选项填入文中空缺处，是短文内容完整、正确。

    Waste can be seen everywhere in the school. Some students ask for more food than they can eat and others

often forget to turn off the lights when they leave the classroom. They say they can afford these things.

1._____.

    Waste can bring a lot of problems. Although China is rich in some resources (资源), 2._____, for example,

fresh water. It is reported that we will have no coal or oil to use in 100 years. So if we go on wasting our

resources, what can we use in the future and where can we move? Think about it. 3._______ Everybody should

stop wasting as soon as possible. 

    4._______ for example, turn off the water taps when we finish washing, turn off the lights when we leave the

classroom, try not to order more food than we need, and so on. Little by little, everything will be changed.

5._______

A. In our everyday life, we can do many things to prevent (阻止) waste from happening.

B. Waste can be stopped one day, if we do our best.

C. we are short of others.

D. I think we should say no to the students who waste things every day.

E. But I don't agree with them.

镜下观察，患牙釉质呈三角形病损，三角形的顶部向着釉牙本质界，底部向着釉质表面，由深层至表层病变可分为透明层、暗层、病损体部和表层。该病变是

A．釉质浑浊症
B．平滑面釉质龋
C．Turner牙
D．窝沟釉质龋
E．牙本质龋

铁质配电箱箱体的铁板厚度为大于（）。

A.1.0mm

B.1.2mm

C.1.5mm

D.2.0mm

动作技能

进入煤气区域工作，携带（）、（）同行。