调节分子量、及密度方法有哪些。

小肠以下部位出血，大便通常不会出现下列哪种情况（）。

A.鲜红色血便

B.暗红色血便

C.柏油便

D.洗肉水样便

E.脓血便

读“我国南、北方水资源、人口及耕地分布对照图，回答1—2题。

1、下列有关图中内容说法正确的是[ ]

A、我国人口重心在北方地区

B、南方的人均耕地面积不到北方的一半

C、人均耕地面积南方多于北方

D、南方的人均水资源为北方的4倍

2、造成我国南方和北方地区水资源总量差异大的主要原因是 [ ]

A、雨季长短导致降水量差异较大

B、耕地面积差异较大

C、城市化水平差异较大

D、纬度差异导致蒸发量差异大

同学们都知道生物体的结构与功能是相适应的。下列有关结构与功能的叙述，正确的是

A．根尖具有分生区，与根的吸收功能相适应

B．毛细血管管壁薄、管内径小，与物质交换的功能相适应

C．叶片中有叶脉，与制造有机物的功能相适应

D．胃壁内有胃腺，与胃的吸收功能相适应

How far would you be willing to go to satisfy your need to know? Far enough to find out your possibility of dying from a terrible disease? These days that’s more than an academic question, as Tracy Smith reports in our Cover Story.

There are now more than a thousand genetic tests, for everything from baldness to breast cancer, and the list is growing. Question is, do you really want to know what might eventually kill you? For instance, Nobel Prize-winning scientist James Watson, one of the first people to map their entire genetic makeup, is said to have asked not to be told if he were at a higher risk for Alzheimer’（老年痴呆症）.

“If I tell you that you have an increased risk of getting a terrible disease, that could weigh on your mind and make you anxious, through which you see the rest of your life as you wait for that disease to hit you. It could really mess you up.” Said Dr. Robert Green, a Harvard geneticist.

“Every ache and pain,” Smith suggested, “could be understood as the beginning of the end.” “That ’s right. If you ever worried you were at risk for Alzheimer’s disease, then every time you can’t find your car in the parking lot, you think the disease has started.”

Dr. Green has been thinking about this issue for years. He led a study of people who wanted to know if they were at a higher genetic risk for Alzheimer’s. It was thought that people who got bad news would, for lack of a better medical term, freak out. But Green and his team found that there was “no significant difference” between how people handled good news and possibly the worst news of their lives. In fact, most people think they can handle it. People who ask for the information usually can handle the information, good or bad, said Green.

小题1:Which of the following is true about James Watson？

A．He doesn’t want to know his chance of getting a disease.

B．He is strongly in favor of the present genetic tests.

C．He believes genetic mapping can help cure any disease.

D．He is more likely to suffer from Alzheimer’s disease.小题2:The first paragraph is meant to__________.

A．ask some questions

B．satisfy readers’ curiosity

C．introduce the topic

D．describe an academic fact小题3:According to Paragraphs 3 and 4, if a person is at a higher genetic risk, it is__________.

A．necessary to remove his anxiety

B．impossible to hide his disease

C．better to inform him immediately

D．advisable not to let him know小题4:The underlined part “freak out” in Paragraph 5 is closest in meaning to“_________”.

A．leave off

B．break down

C．drop out

D．turn away小题5:The study led by Dr. Green indicates that people__________.

A．can accept some bad news

B．tend to find out the truth

C．prefer to hear good news

D．have the right to be informed

软组织血管瘤的CT表现，正确的有（）。

A.软组织肿块形态不规则、边界不清

B.海绵状血管瘤常伴脂肪组织增生，多位于肌间或肌内呈不均匀低密度区

C.钙化及静脉石常见，为本病的重要诊断依据

D.病变内血管和血池可呈点状和迂曲的线状结构

E.增强扫描，病变明显强化