求[tex=1.571x1.0]RNtI0NKH2g6KEN9fOQQ9yA==[/tex], 设 :[tex=6.429x1.357]an6s81hA/fD9v3a5uqlwxN+kMBu6NNeo1HIsMokJuB0=[/tex]

抽取一个容量为100的随机样本,其均值为[img=12x19]17e0b1b470ee3ff.png[/img]=81,标准差s=12。总体均值μ的99%的置信区间为( )。 A: 81±1.97 B: 81±2.35 C: 81±3.10 D: 81±3.52

Sapevi<br/>che Giorgio ha cambiato casa? Sì,______ . No,______ .

读音标，选单词。haʊs/ A: house B: horse

流感病毒共有（）种HA。 A: 6 B: 9 C: 12 D: 15

Look at this lovely girl!Who is she? Ha, Ha! It's me.I'mvocational school student. I am good at English,Math and PE.<br/>I like reading, singing, dancing and listening to pop music.<br/>What does the writer do?__________ A: She's adoctor B: She's a cashier C: She's a nurse D: She's a student

阅读材料：Look at this lovely girl!Who is she? Ha, Ha! It's me.I'm a vocational school student. I am good at English,Math and PE.I like reading, singing, dancing andlistening to pop music.题目：What does the writer do?_____D_____ A: She's a doctor. B: She's a cashier. C: She's a nurse. D: She's a student.

原文：Look at this lovely girl!Who is she? Ha, Ha! It's me.I'mvocational school student. I am good at English,Math and PE.<br/>I like reading, singing, dancing and listening to pop music. 题目：What does the writer do?__________ A: She's a doctor. B: She's a cashier. C: She's a nurse. D: She's a student.

c(HA)=0．050mol．L—1的溶液的pH=5．35，则HA的KaΘ等于()。 A: 2．0×1011 B: 4．0×1010 C: 4．5×10—6 D: 8．9×10—5

设A是3阶方阵，且|A|=3，则|2A|=____________。 A: 6 B: 12 C: 24 D: 81