5个人排成一排,其中甲、乙两人至少有一人在两端的排法种数有( )。

题型:填空题

问题:

5个人排成一排,其中甲、乙两人至少有一人在两端的排法种数有(    )。

考点:排列与组合
题型:填空题

大棚蔬菜种植可以弥补蔬菜的季节性不足,满足人们对蔬菜的多元化需求.下列哪些措施可提高大棚蔬菜产量(  )

①增加光照时间  ②合理密植③适度增加大棚中的二氧化碳.

A.①

B.①③

C.②③

D.①②③

题型:填空题

妊娠初期及哺乳期妇女禁用

A.含有右美沙芬的制剂
B.含有解热镇痛药制剂
C.含有抗过敏药制剂
D.含有对乙酰氨基酚的制剂
E.含有鼻黏膜血管收缩药的制剂

题型:填空题

A small piece of fish each day may keep the heart doctor away. That’s the finding of a study of Dutch men in which deaths from heart disease were more than 50 percent lower among those who consumed at least an ounce of salt water fish per day compared to those who never ate fish.

The Dutch research is one of three human studies that give strong scientific support to the long held belief that eating fish can provide health benefits, particularly to the heart.

Heart disease is the number-one killer in the United States, with more than 550,000 deaths occurring from heart attacks each year. But previous research has shown that the level of heart disease is lower in cultures that consume more fish than Americans do. There are fewer heart disease deaths, for example, among the Eskimos of Greenland, who consume about 14 ounces of fish a day, and among the Japanese, whose daily fish consumption averages more than 3 ounces.

For 20 years, the Dutch study followed 852 middle-aged men, 20 percent of whom ate no fish. At the start of the study, average fish consumption was about two-thirds of an ounce each day, with more men eating lean fish than fatty fish.

During the next two decades, 78 of the men died from heart disease. The fewest deaths were among the group who regularly ate fish, even at levels far lower than those of the Japanese or Eskimos. This relationship was true regardless of other factors such as age, high blood pressure, or blood cholesterol(胆固醇)levels.

小题1:The passage is mainly about _________.

A.the high incidence of heart disease in some countries

B.the changes in people’s diet

C.the effect of fish eating on people’s health

D.the daily fish consumption of people in different cultures小题2:We can infer from the passage that there are fewer heart disease deaths ________.

A.in countries of the yellow-skin race

B.in highly-developed countries

C.in the countries with high consumption of fish

D.in the countries with good production of fish小题3:The phrase “this relationship” in paragraph 6 refers to the connection between _________ and the level of heart disease.

A.the amount of fish eaten

B.regular fish-eating

C.the kind of fish eaten

D.people of different areas小题4:From the passage we know the author is most probably ______.

A.a heart doctor

B.a science researcher

C.a supporter of healthy eating

D.a university student

题型:填空题

Safe water buoys may show ONLY().

A.flashing red lights

B.flashing green lights

C.white lights

D.yellow lights

题型:填空题

华为建全球第一GRPRS UMTS PS核心商用网。

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