分层抽样与整群抽样的具体操作方法是怎样的?二者之间有何异同?什么情况下应选用分层抽样?什么情况下则应选用整群抽样?
指出下列各字中哪些是形声字,然后用“从某、某声”的术语分析这些形声字的结构:
(1)河;
(2)鸣;
(3)相;
(4)宇;
(5)衢;
(6)美;
(7)徒;
(8)兼;
(9)魂;
(10)顿;
(11)行;
(12)刃;
(13)谋;
(14)首;
(15)红;
(16)囚;
(17)苗;
(18)理;
(19)本;
(20)崇。
某市卫生局接到报告,2005年3月2日,某市报告某社区出现疑似人禽流感病例 。作为疾控中心工作人员,你被委派到该社区发病现场采样 。
问题:
1.你认为采样的对象、采样时间、采样种类有何要求?
2.可疑标本采样时应注意什么问题?
3.采集可疑标本样品的包装和运输过程中的注意要点 。
根据题目要求完成下列任务, 用国家通用语言文字作答。
下面教学片段来自某初中英语教师的口语教学。
T:OK. Let's practice this dialogue.
Ss: ... (Ss don't know what to do.)
T: Well, you ask your partner "Do you like bananas?", your partner answers "Yes, I do." If he or she doesn't like, then say “No, I don't like it". Understand now?
Ss: OK.
(Ss read out the dialogue in the textbook in pair)
T: Now. (to one student) Does your partner like bananas?
S1: Yes, he does.
T: (to another student) Does your partner like bananas?
S2: No, he don't.
T: No, no, no, no. He doesn't!
S2: Oh. Oh. Yes .He doesn't.
T: You must pay attention to that. OK? Now please read after me. Do you like bananas?
Ss: (in chorus) Do you like bananas?
T: Yes, I do.
Ss (in chorus) Yes, I do.
根据所给信息回答下面问题:
(1)该教学片段属于哪个教学环节( 3分)?其教学目的是什么?(1分)
(2)指出该教学片段存在的三个问题 。( 12分)
(3)如何针对上述问题进行相应的改进?(12分)