某分部工程中各项工作间逻辑关系见下表，相应的双代号网络计划如下图所示，图中的错误有（

小明在东西大路上跑步，他先向东跑1000m，又向西跑了800m，此时，小明在出发点什么方向？距出发点多远？

一变：小明在东西大路上跑步，规定向东为正，他先向东跑了1000m，又向东跑了-800m，此时小明在出发点什么方向？距出发点多远？

二变：小明在东两大路上跑步，规定向东为正，他先向东跑了1000m，又跑了一段之后，他位于出发点西边200m处，问小明第二段向什么方向跑了多远？

埃及胡夫金字塔上有这样一段令人生畏的铭文：“不论谁骚扰了法老的安宁，死神之翼必将降临到他的头上。”从哲学派别上看，铭文的观点属于  

肝硬化门静脉高压时不出现

A．腹壁静脉曲张

B．食管静脉曲张

C．痔静脉曲张

D．胃底静脉曲张

E．胸壁静脉曲张

In the summer of 1978 an English farmer was driving his tractor through a field of wheat when he discovered that some of his wheat was lying flat on the ground. The fattened (压平的) wheat formed a circle about six meters across. Around this circle were four smaller circles of flattened wheat. The five circles were in a formation like five dots. During the following years, farmers in England found the strange circles in their fields more and more often.

The circles are called “crop circles” because they appear in the fields of grain - usually wheat or corn. The grain in the circles lies flat on the ground but never broken; it continues to grow, and farmers can later harvest it. Farmers always discover the crop circles in the morning, so the circles probably form at night. They appear only in the months from May to September.

At first, people thought that the circles were a hoax. Probably young people were making them as a joke, or farmers were making them to attract tourists. To prove that the circles were a hoax, people tried to make circles exactly like the ones that farmer had found. They couldn’t do it. They couldn’t enter a field of grain without leaving tracks(痕迹), and they couldn’t flatten the grain without breaking it.

Many people believe that beings from outer space are making the circle to communicate with us from far away and that the crop circles are messages from them.

Scientists who have studied the crop circles suggested several possibilities. Some scientists say that a downward rush of wind leads to the formation of the circles - the same downward rush of air that sometimes causes an airplane to crash. Other scientists say that forces within the earth cause the circles to appear. There is one problem with all these scientific explanations: crop circles often appear in formations, like the five-dot formation. It is hard to believe that any natural force could form those.

小题1:In the summer of 1978, an English farmer discovered in his field that __________.

A．some of his wheat had been damaged

B．his grain was growing up in circles.

C．his grain was moved into several circles

D．some of his wheat had fallen onto the ground.小题2:According to the text, the underlined part “hoax” (in the 3^rd paragraph) probably means __________.

A．an attempt made to fool people

B．a special way to plant crops

C．a research on the force of winds

D．an experiment for the protection of crops.小题3:Which of the following may prove that the crop circles are not made by man?

A．The farmer couldn’t step out of the field.

B．The farmers couldn’t make the circles round.

C．The farmers couldn’t leave without footprints.

D．The farmers couldn’t keep the wheat straight up.小题4:A proper title for this passage is ___________.

A．An Unsolved Mystery

B．Strange Flying Objects

C．The Power of Natural Forces

D．The discovery of Strange Circles

对照组不加任何处理的对照是

A．空白对照
B．实验对照
C．标准对照
D．自身对照
E．相互对照