已知关于x的方程3a-x=x2+3的解是4，则-a2-2a=______．

目前，中国保监会规定保险公司应至少将分红保险业务当年度可分配盈余的______分配给客户。

A．50%
B．60%
C．70%
D．80%

There are many things you can do to improve your memory. Among them are many kinds of useful ways are well as taking special care of your health.

It is important that you make yourself excited to make your memory more active. You can do this by doing some new activities and by changing your daily habits. Learning a new skill helps your brain（大脑）to develop. When trying to remember something, you should pay special attention to the most important things about it .Do not allow other thoughts to enter your mind because this will reduce your chances of making right memories. An excellent way to help memory is to connect information with pictures. Try to see the pictures in your mind. Taking notes and keeping a diary will also be helpful.

Healthy food and plenty of vitamins are necessary for your memory to work well. Drinking a lot of water also helps keep your memory. You must allow your brain to have enough sleep and rest. When you are asleep, your brain stores memory. Not enough sleep can cause problems with storing information .And being tired will also stop you from being able to think clearly and well.

In order to keep your mind on your work, you must be free from worry. Generally keeping fit and normal health checks are both important as well-not just for improving your memory.

建设项目经济评价的计算期是指（）。

A.从建成投产到主要固定资产报废为止所经历的时间 

B.从开始施工到建成投产所经历的时间 

C.从开始施工到建成投产，直至主要固定资产报废为止所经历的时间 

D.从开始施工到建成投产，直至全部固定资产报废为止所经历的时间

脚手架工程不包括( )。

A．设计计算

B．绘制施工详图

C．编制搭设和拆除方案

D．操作措施方案

关于化合水，下列说法不正确的是（）。

A.煤中的化合水是指以化学方式与矿物质合成的，在全水分测定后仍保留下来的水

B.化合水就是通常所说的结晶水和结合水之外的合成水

C.化合水含量不大，而且必须要在更高的温度下才能失去

D.在煤的工业分析中，一般不考虑化合水