问题
单项选择题 A2型题
男性，33岁，便血1年，初为排便后有少量鲜血滴出，无痛，便后出血自行停止，近半年来偶有块状物自肛门脱出，便后自行回缩，最可能的诊断是（）
A.直肠癌
B.混合痔
C.外痔
D.直肠脱垂
E.内痔
答案
参考答案：E
解析：内痔主要临床表现是出血和脱出。无痛性间歇性便后出鲜血是内痔。未发生血栓、嵌顿、感染时单纯性内痔无疼痛。
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男性，33岁，便血1年，初为排便后有少量鲜血滴出，无痛，便后出血自行停止，近半年来偶有块状物自肛门脱出，便后自行回缩，最可能的诊断是（）
A.直肠癌
B.混合痔
C.外痔
D.直肠脱垂
E.内痔
参考答案：E
解析：内痔主要临床表现是出血和脱出。无痛性间歇性便后出鲜血是内痔。未发生血栓、嵌顿、感染时单纯性内痔无疼痛。
Passage Three
| For centuries, explorers have risked their lives venturing into the unknown for reasons that were to varying degrees economic and nationalistic (国家主义的). Columbus went west to look for better trade routes to the Orient and to promote the greater glory of Spain. Lewis and Clark journeyed into the American wilderness to find out what the U. S. had acquired when it purchased Louisiana, and the Appolo astronauts rocketed to the moon in a dramatic show of technological muscle during the cold war. Although their missions blended commercial and political military imperatives, the explorers involved all accomplished some significant science simply by going where no scientists had gone before. Today Mars looms (隐约出现) as humanity’s next great terra incognita (未探明之地). And with growing emphasis on international cooperation in large space ventures, it is clear that imperatives (需要，必要) other than profits or nationalism will have to compel human beings to leave their tracks on the planet’s reddish surface. Could it be that science, which has long played a minor role in exploration, is at last destined to take a leading role The question naturally invites a couple of others: Are there experiments that only humans could do on Mars Could those experiments provide insights profound enough to justify the expense of sending people across inter- planetary space With Mars the scientific stakes are arguably higher than they have ever been. The issue of whether life ever existed on the planet, and whether it persists to this day, has been highlighted by mounting evidence that the Red Planet once had abundant stable, liquid water and by the continuing controversy over suggestions that bacterial fossils rode to Earth on a meteorite (陨石) from Mars. A more conclusive answer about life on Mars, past or present, would give researchers invaluable data about the range of conditions under which a planet can generate the complex chemistry that leads to life. If it could be established that life arose independently on Mars and Earth, the finding would provide the first concrete clues in one of the deepest mysteries in all of science: the prevalence of life in the universe. |
By saying "With Mars the scientific stakes are arguably higher than they have ever been" (Line 1, Para.4), the author means that______.
A．with Mars the risks involved are much greater than any previous space ventures
B．in the case of Mars, the rewards of scientific exploration can be very high
C．in the case of Mars, much more research funds are needed than ever before
D．with Mars, scientists argue, the fundamental interests of science are at issue