题目内容：

    Barbara McCintock was one of the most import scientists  of the twentieth century．She made important discoveries about genes（基因） and chromosomes （染色体）．

Barbara McClintock was born in 1902 in Hartford，Connecticut．Her family moved to Brooklyn area of new York City in 1908．Barbara was an active child with interests in sports and music． She also developed an interest in science．

She studied science at Cornell University in Ithaca， New York． Barbara was among a small number of undergraduate students to receive training in genetics in 1921． Years later， she noted that few college students wanted to study genetics．

Barbara McClintock decided to study botany， the scientific study of plants， at Cornell University． She completed her undergraduate studies in 1923． McClintock decided to continue her education at Cornell． She completed a master‘s degree in 1925． Two years later， she finished all her requirements for a doctorate degree．

McCintock stayed at Cornell after she completed her education． She taught students botany． The 1930s were not a good time to be a young scientist in the United States． The country was in the middle of the great economic Depression． Millions of Americans were unemployed． Male scientists were offered jobs． But female geneticists were not much in demand．

An old friend from Cornell， Marcus Rhoades， invited McClintock to spend the summer of 1941working at the Cold Spring Harbor Laboratory． It is a research center on Long Island， near New York City． McClintock started in a temporary （临时的） job with the genetics department． A short time later， she accepted a permanent （永久的） position with the laboratory． This gave her the freedom to continue her research without having to teach or repeatedly ask for financial aid．

By the 1970s， her discoveries had had an effect on everything from genetic engineering to cancer research． McClintock won the Nobel Prize for Physiology or Medicine in 1983for her discovery of the ability of genes to change positions on chromosomes． She was the first American woman to win an unshared Nobel Prize．

1.When did McClintock receive a doctorate degree？

A. In 1921．

B. In 1923．

C. In 1925．

D. In 1927．

2.During the great economic Depression in the US，     ．

A. young scientists had trouble finding a job

B. female geneticists were not wanted at all

C. male geneticists were in great demand

D. male scientists were out of job

3.McClintock was awarded a Nobel Prize because of     ．

A. her research in botany

B. her contribution to genetic engineering

C. her discoveries about genes and chromosomes

D. her unshared work in the laboratory

4.The text is likely to appear in

A. a biography

B. a history paper

C. a newspaper

D. a philosophy textbook