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问题 填空题

圆锥的轴截面是顶角为120°的三角形，如果它的高是3，则此圆锥的侧面积为______．

答案

过点A作AD⊥BC，

∵圆锥的轴截面是顶角为120°的三角形，它的高是3，

∴AD=3，∠DAC=∠BAD=60°，

∴∠C=30°，

∴AC=6，CD=3

3
，

∴圆锥的母线为：6，底面半径为：3

3
，圆锥的底面周长为2π×3
3
=6
3
π，

它的侧面展开图的弧长为：6

3
π，

所以它的侧面展开图的面积为：

1
2
×6×6
3
=18
3
π，

故答案为：18

3
π．

单项选择题 A1/A2型题

HIV与感染细胞膜上CD4分子结合的病毒刺突是（）

A.gp120

B.gp41

C.P24

D.P17

E.gp160
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单项选择题

Euthanasia has been a topic of controversy in Europe since at least 1936. On an average of six times a day, a doctor in Holland practices "active" euthanasia: (1) administering a lethal drug to a (2) ill patient who has asked to be relieved (3) suffering. Twenty times a day, life prolonging treatment is withheld or withdrawn (4) there is no hope that it can (5) an ultimate cure. "Active" euthanasia remains a crime on the Dutch statute books, punishable (6) 12 years in prison. But a series of court cases over the past 15 years has made it clear that a competent physician who (7) it out will not be prosecuted.

Euthanasia, often called "mercy killing", is a crime everywhere in Western Europe. (8) more and more doctors and nurses in Britain, Germany, Holland and elsewhere readily (9) to practicing it, most often in the "passive" form of withholding or withdrawing (10) The long simmering euthanasia issue has lately (11) into a sometimes fierce public debate, (12) both sides claiming the mantle of ultimate righteousness. Those (13) to the practice see themselves (14) sacred principles of respect for life, (15) those in favor raise the banner of humane treatment. After years (16) the defensive, the advocates now seem to be (17) ground. Recent polls in Britain show that 72 percent of British (18) favor euthanasia in some circumstances. An astonishing 76 percent of (19) to a poll taken late last year in France said they would like the law changed to (20) mercy killings. Obviously, pressure groups favoring euthanasia and "assisted suicide" have grown steadily in Europe over the years.

20（）

A.refuse

B.evaluate

C.decriminalize

D.counter
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