主要根据暴露状况来抽取样本的研究是（） A.描述性研究 B.队列研究 C.病例对照

照样子，画线的词写句子。

1．官员们一边看，一边议论。

2．瓶子里的水渐渐升高了。

3．别的小朋友都慌了，有的吓哭了，有的叫着喊着，跑去找大人。

在边长为a的正方形土地上修建边长为b的正方形水池（a＞b），剩余土地的面积为[ ]

A.（a-b）²

B.a²-b²

C.（a+b）²

D.a²+b²

补写出下列名句名篇中的空缺部分。

（1）塞上长城空自许，__________________。出师一表真名世，__________________！（陆游《书愤 》）

（2）__________________，一弦一柱思华年。庄生晓梦迷蝴蝶，__________________。（李商隐《锦瑟 》）

（3）驾一叶之扁舟，举匏尊以相属；__________________，__________________。（苏轼《赤壁赋》）

（4）多情自古伤离别，__________________！今宵酒醒何处？__________________。（柳永《雨霖铃》）

女性患者，56岁。近2个月内出现5次突然不能言语伴右侧肢体无力，每次持续6～15分钟。既往有严重神经官能症和头痛病史。现神经系统检查正常

比较有价值的辅助检查是（）.

A.腰穿检查脑脊液

B.头颅X光平片

C.脑电图检查

D.经颅多普勒超声检查

E.心理检查

On any weekend throughout the year one can spend hours browsing through neighborhood flea (跳蚤) markets. These are very popular for those who are in search of bargains and who have a keen eye for picking through what others have discarded. They hunt and search for something they can reuse. Americans love secondhand merchandise (商品) which can be bought cheaply and restored to its original use. In many cases the condition and the quality are still good, though the style might be outdated.

For some people searching through flea markets is a hobby which reaps rewards. They look for possible antiques among the items for sale or for old furniture which can be restored with a little care and used again. Many wise collectors often find rare items worth much more than their bargained price. Since prices are usually not fixed, if one is persistent a bargain can easily be struck. The owner may be selling a rare collectable and may not even be aware of its value. One of the great pleasures of shopping at such markets is the chance to bargain with the shop owner and settle for a price which one can afford and is willing to pay.

Perhaps even more enjoyable than flea markets are the weekend outdoor garage sales which have now become very much a part of American culture. These are held usually in the spring and fall when the weather is still good. Usually a homeowner, having decided that he would like to clear his residence of accumulated items which are no longer useful to him, advertises in a local paper that he is holding a garage sale. More than likely the goods on display are in good condition and great buys can be found if one has the time and patience to search carefully. The home owner places items for sale on display along the driveway leading to his garage or on his front lawn and waits for people to look at what he has to sell. Old magazines, books, paintings, bicycles, ice-skates, items of clothing and electrical appliances of every sort appear on a regular basis. If the owner is in a position where he must sell his home or plans to move soon, then he may be forced to practically give things away at a price far below their true worth.

1. What do you usually do before holding a garage sale?

A. Put on an advertisement in a local newspaper.  

B. Display your goods in front of the garage.

C. Find rare items and fix their prices.         

D. Clear your garage and front lawn.

2. The underlined word “discarded” in Paragraph 1 probably means ____.

A. distributed                B. rejected               C. discovered          D. stored

3. When people shop at a flea market, how can they settle on a price?

A. They can bargain on a price acceptable to both. B. They can question their value.

C. They can expect a 50% discount.             D. They can compare with the other sellers.

4. What do we know about the garage sale?

A. It is only held in the spring of the year.

B. The goods on display are totally useless.

C. Garage sales are popular with Americans.  

D. All the goods are selling far below their real value.