问题 单项选择题

疾病的流行是指

A.发病率超过10%。

B.某病的发生频率明显超过该地历年同期的水平

C.某病的发病率虽然较低,但在该地人群中长年存在

D.在局限范围短时间内出现大量相同病例的现象

E.某病在一定地区长期存在的现象

答案

参考答案:B

解析:本题的考点是“流行”这一概念。“流行”是反映疾病发生发展的强度的指标,具体地讲,是指某病的发生频率明显超过该地区历年同期水平的现象。

单项选择题

Congress makes the laws in the United States. It has two pans, which are more or less equal in power. They are known as the House of Representatives and the Senate. The House of Representatives is larger than the Senate whose 100 members (two from each state) serve for six years. The 435 members of the House are elected every two years, and the number from each state is determined by the population of the state. For example, California, which has a large population, has 43 representatives, while the State of Nevada has only one.

The House and Senate are divided into small groups which take care of special matters such as education or foreign affairs. The most important work of Congress is often done in these groups, which are called subcommittees.

According to the Constitution of the United States, a senator must be at least 30 years old and he must have been a citizen of the United States for nine years at the time of his election. To be elected to the House a person must be 25 years old and must have been a United States citizen for seven years. At the present time, members of Congress include businessmen, farmers, teachers, and especially lawyers. In general, senators are better known than representatives because they are fewer in number and serve for a longer time. Many American presidents served in Congress before they became president.

Which of the following is true().

A. A representative serves for two years.

B. To become a senator is easier than to become a representative.

C. A senator performs his duties for a shorter time than a representative.

D. All presidents were representatives and then senators before becoming president of the United States.

多项选择题