听第12段对话,回答第13至15小题。()13.WhathappenedtoLily'snewEnglishteacher?A.Hehadabadcold.B.Hehadanaccident.C.Hehadabadcough.()14.WhatwillLilydoonSunday?A.Goclimbi
听第12段对话,回答第13至15小题。
( )13. What happened to Lily's new English teacher?
A. He had a bad cold.
B. He had an accident.
C. He had a bad cough.
( )14. What will Lily do on Sunday?
A. Go climbing. B. Take an exam.
C. Stay at home and study.
( )15. What's the possible relationship between the two speakers?
A. Teacher and student.
B. Father and daughter.
C. Husband and wife.
以知a=1,b=2求1/ab+1/[a+1][b+1]+1/[a+2][b+2]+.+1/[a+2 2020-04-15 …
设集合A={1,a,b},B={a,a^2,ab}且A=B,求实数A,B的值因为集合需要满足互异性 2020-05-15 …
1.[a/(ab-b²)-b/(a²-ab)]÷[1+(a²+b²)/2ab],其中a=-1+根号 2020-05-16 …
若|ab-2|+|b-1|=0,试求1/ab+1/(a+1)(b+1)+1/(a+2)(b+2)+ 2020-05-20 …
已知|ab-2|与|a-1|互为相反数求值1/ab+1/(a+1)(b+1)+1/(a+2)(b+ 2020-06-03 …
问个题袄西西如果|ab-2|+|b-1|=0那么ab/1+(a+1)*1/(b+1)+1/(a+2 2020-06-27 …
如果有理数a,b满足|ab-2|+|1-b|=0.试求1/ab+1/(a+1)(b+1)+1(a+ 2020-07-09 …
立方差公式的推广证明过程(1)a^n-b^n=(a-b)[a^(n-1)+a^(n-2)*b+.. 2020-07-11 …
基本不等式设数列a(n),b(n),且a(1)>b(1)>0,a(n)=(a(n-1)+b(n-1 2020-08-03 …
设a、b、c为正数,且a^2+b^2+c^2=3,证明:1/(1+2ab)+1/(1+2bc)+1/ 2020-11-06 …