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【单选题】
为研究职业接触放射性物质与骨瘤发生的关系，某人选取1000名接触放射性物质的女职工和l000名电话员作为研究对象，观察l950～1980年间的骨瘤发生率，结果接触放射性物质的女工中有20例骨瘤患者，而电话员中仅有4例，这种研究属于A.
横断面研究
B.
实验研究
C.
队列研究
D.
临床研究
E.
病例对照研究
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举一反三
【单选题】In the sentence “Do not leave your money in a piggy bank or under your mattress”, the phrase “piggy bank” means ( ).
A.
a relatively small bank
B.
a relatively infamous bank
C.
a small container that is used for saving money
【单选题】The phrase 'increment, earned though not received' in the third paragraph means ____.
A.
money one has earned and will be paid later
B.
money one has earned, but will not be paid to him/her
C.
something that one earns through a job, but is not counted in terms of pay
D.
something that onereams that has nothing to do with his or her job
【简答题】色约占整个空间25%的面积,是决定空间色彩形象的色彩。
【单选题】which phrase has the similar meaning to "to make a person do something that they do not want to do?"
A.
allow sb to do sth
B.
refuse sb to do sth
C.
force sb to do sth
D.
remind sb to do sth
【简答题】简述基因工程的概念和步骤。
【单选题】Materials science can also do the converse: As desirable properties are defined, the material that can display them, although it might not exist in nature, is designed.What does the phrase "do the con...
A.
make an effect
B.
make every effort
C.
do sth from the opposite way
D.
prevent sb from doing sth
【简答题】基因工程的概念? 基因工程四要素? 基因工程的优点? 基因工程的诞生?
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