问题 单项选择题

地质图上表现为中间老、两侧变新的对称分布地层,这种构造通常是( )。

A.正断层
B.逆断层
C.向斜
D.背斜

答案

参考答案:D

解析: 褶皱构造有背斜和向斜两种基本形态,背斜是岩层向上拱起弯曲,由于风化侵蚀,背斜核心部分的岩层时代较老,两侧岩层时代依次对称变新。向斜是岩层向下凹陷弯曲,由于沉积等作用,核心部分的岩层时代较新,两侧岩层依次对称变老。断层是岩体受力作用断裂后,两侧岩块沿断裂面发生显著位移的断裂构造,没有题干中所说的构造特点。

问答题
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 Twenty times a day, life prolonging treatment is withheld or withdrawn (4) there is no hope that it can (5) an ultimate cure.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.

6()

A.for

B.in

C.to

D.by