According to a new study. ______.
A. sex ratio is determined by where people live
B. sex ratio at birth is skewed all over the world
C. the skewed sex ratio is a natural phenomenon
D. the percentage of boys born varies with latitude
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According to the text. Congress
A. gives workers a chance for a fair hearing in federal court
B. grants Americans the right to sue for age-discrimination
C. vindicates the legal rights of Americans in federal court
D. waives the right of Americans to sue for discrimination
马来酸氯苯那敏抗过敏作用的机理是()
A. 激动H1受体
B. 阻断H1受体
C. 激动H2受体
D. 阻断H2受体
E. 激动H1受体
辐射类型包括辐射种类和能量。它们首先取决于源中放射性核素的()。
A. 种类
B. 数量
C. 活度
D. 半衰期
People who feel powerless______.
A. are excessively concerned with circumstances
B. tend to reprove somebody for their deficiencies
C. have neither formal nor informal education at all
D. feel resentful towards their parents and employers
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