某医务室用抽签法抽取10名氟作业工人，测定其工前、工中、工后4小时的尿氟浓度，问氟作
题型：单项选择题 A1型题
问题：
某医务室用抽签法抽取10名氟作业工人，测定其工前、工中、工后4小时的尿氟浓度，问氟作业工人在这三个不同时间的尿氟浓度有无差别。观察对象的抽取属（）抽样方法。
A.单纯随机
B.系统随机
C.分层随机
D.整群随机
E.多阶段随机
题型：单项选择题 A1型题
In American schools there is something called Home-coming Day. Many high schools and colleges with a football team have a home-coming game. This can be the most important event of the year except graduation (毕业) day. Students plan Home-coming Day for many weeks in advance.
Several days before Home-coming ,students start to decorate (装饰)the school. There are signs to wish luck to the team, and many other signs to welcome all the graduates. Many people still come to Home-coming twenty or thirty years after their graduation.
The members of school clubs build booths (摊位) and sell lemonade, apples and sandwiches. Some clubs help to welcome visitors.
During the day people like to look for teachers that they remember from long ago. Often they see old friends and they talk together about those happy years in school.
Everyone soon comes to watch the football game. When the game is half over, the band (乐队)comes onto the field and plays school songs. Another important moment is when the Home-coming Queen or King appears. All the students vote a most popular student Home-coming Queen or King. It is a great honor to be chosen.
Home-coming is a happy day, but it is not perfect unless the football team wins the game. Even if the team loses, the students still enjoy Home-coming. Some stay at the school to dance, and others go to a party. For everyone it is a day worth remembering.
小题1:The most important event of the year in high schools and colleges is_______.
A．Home-coming
B．the football game
C．graduation
D．winning the game小题2:When do students begin to do everything for Home-coming?
A．The day before Home-coming.
B．Many weeks before the day.
C．When the guests arrive.
D．Several hours before Home-coming.小题3:Which of the following is NOT mentioned (提及) on Home-coming Day?
A．To see old friends.
B．To visit teachers they remember.
C．To watch the football game.
D．To go home to see their family.小题4:Who can probably become Home-coming Queen or King?
A．The teacher who is kind to the students.
B．The student who is popular with the students.
C．The visitor who is famous to the students.
D．The player who plays best in the football game.小题5:What’s the best title of this article?
A．Home-coming Day
B．A Happy Day
C．The Most Important Event
D．Home-coming Queen or King