In a circular motion, the acceleration is always perpendicular to the velocity.

The mystery in question is none other than the human embryo cloned a la Dolly. The aim is not to produce people. Through "therapeutic"(治疗的)cloning, scientists would create embryos to harvest stem cells, which may hold the key to treating a wide range of disease. But like most passionate debates, the real issue 一 commercialization 一 sits quietly in the background of the emotional chaos. The debate erupted across the industrially advanced world on January 22nd when Britain became the first European country to legalize the creation of cloned human embryos. Members of the European Parliament almost immediately expressed their shock and condemned the decision. Yet in many ways, the new law is a logical extension of rules dating back over a decade. Since 1990, UK researchers could create and use embryos for limited research purposes, namely to treat infertility and detect birth defects. The new law widens the field of study to include stem cells, which experts say could revolutionize medicine, offering the possibility of transplants to treat scores of illnesses from Parkinson's disease to diabetes (糖尿病).No one has yet applied for a license to perform. such experiments, according to the Human Fertilisation and Embryology Authority, which will carefully screen each request. No other uses of cloning would be allowed and a new law has been promised to explicitly (明确地)ban reproductive cloning.

As expected, the most rigid opposition has come from the Catholic Church, which considers the embryo to be a living person from the moment of conception. Cloning aside, even research involving "spare" embryos (created for infertility treatments but not used. is condemned because it is morally wrong to use a person for the benefit of someone else. At the opposite end of the spectrum (范围)lie the hardcore utilitarians (功利主义)of science and business, who are generally astute (精明的)enough not to announce their politically incorrect views: namely that the embryo isjust another batch of cellular sludge (淤积;淤沉)that can and should be used like any other biological resource in the pursuit of medical research.

1.The purpose of therapeutic cloning is to.()

A.produce people

B.commercialize stem cells

C.treat various diseases

D.clone human embryo in Dolly

2.What triggered the debate across the industrial countries?()

A.The commercialization of cloned human embryos.

B.Legalizing the creation of cloned human embryos in Britain.

C.A theoretical flaw in the experiment of human embryos cloning.

D.The European Parliament's harsh criticism on the UK's decision.

3.In the 1990s the British researchers use embryos basically to.()

A.harvest stem cells

B.reform. the system of medical care

C.treat infertility and detect birth defects

D.study the possibility of organ transplants

4.The Catholic Church argue against human embryos cloning because.()

A.cloning creates spare embryos

B.it considers the embryo to be a living person

C.it may lead to reproductive cloning

D.it's morally wrong to use a person for the benefit of another one

5.The utilitarians of science and business think.()

A.human embryos cloning is a hard choice

B.it's politically incorrect to clone human embryos

C.the embryos should be used like any other biological resource

D.human embryos are important samples in the pursuit of medical research

A、we live figuratively in a larger societal cavern and have to work hard to get out of it

B、we are chained in legs and necks

C、there are shadows in the cave

D、what we see are not real

A、A. researching sales statistics

B、B. being responsible for the board of directors

C、C. overseeing all marketing, advertising and promotional activities

D、D. evaluating customer research, market conditions, competitor data

An object moving in r =100m circle satisfies:, how much is the magnitude of acceleration when t=1s?

A、

B、

C、

D、

A、

B、

C、

D、