定额的特点中，工程建设定额的( )首先体现在定额是在认真研究客观规律的基础上，自觉

Shopping on the Internet is becoming more and more popular. Why do people use the Internet to shop? Some people say it is more convenient. They don’t have to leave their homes to order something; they can shop for anything they want at any time; they can find things for sale that they can’t find in the stores near their homes. Still other people say they can find better prices on the Internet.

If you want to buy something on the Internet, you need a credit(信用) card. You have to type your credit card number and information on the website(网页) and send them to the store over the Internet. You have to be sure that the store will not use your information in the wrong way. You don’t want someone to get your credit card number, so be careful with it, beause people sometimes steal(窃取) credit card numbers from stores.

The Internet is also a good place to go window-shopping. Window-shopping is when you look at the things for sale in a store, but don’t plan to buy anything. In window-shopping you can see what kinds of things you are able to get and how much they cost. Some stores like Ross Stores have a website for information about their stores, but not for shopping. Some stores have a website for information about their stores, and can shop on-line there, such as Office Depot, Payless Shoe Source, Safeway. Some stores like Amazon. com are only for on-line shopping.

小题1: Some people use the Internet to shop because ________.

A．they can sleep all day long

B．they want to leave their homes

C．they want to play with their friends

D．they can get things with less money小题2:The Chinese meaning of the word “convenient” in this passage is “________”.

A．时髦的

B．较近的

C．方便的

D．可用的小题3:If you want to shop on the Internet, you need ________.

A．an ID card

B．a credit card

C．an IC card

D．a room card小题4: Which of the following is NOT true according to the passage?

A．You can shop on-line at www.officedepot.com

B．You cannot shop on-line at www.rossstores.com

C．You can only do window-shopping at www.amazon.com

D．You can do window-shopping and shop on-line at www.safeway.com

已知0.1 mol·L^－1的二元酸H₂A溶液的pH＝4，则下列说法中正确的是 [ ]

A．在Na₂A和NaHA溶液中，离子种类不相同

B．在NaHA溶液中一定有：c(Na⁺) + c(H⁺) ＝ c(HA^－) + c(OH^－) + 2 c(A^2－) 

C．在Na₂A溶液中一定有：c(OH^－) ＝ c(H⁺) + c(HA^－) + c(H₂A) 

D．在溶质物质的量浓度相等的Na₂A和NaHA溶液中，阴离子总数相等

下列哪个不是控制混杂偏倚的手段（）

A.限制

B.匹配

C.随机化

D.分层分析

E.研究对象有代表性

在砖基础的砌筑施工中，为增加基础及上部结构刚度，砌体结构中防潮层与地圈梁合二为一，地圈梁高度为( )mm。

A．150～200
B．200～300
C．180～300
D．150～300

（）又称维修作业调度令，或作业传票。是最基本的生产凭证之一。