-doesyourschoolhavetheparents'meeting?-Twiceayear.()A.HowoftenB.HowlongC.HowmanyD.Howmuch
- does your school have the parents'meeting?
-Twice a year.( )
A. How often
B. How long
C. How many
D. How much
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A={(X,Y)|X+Y=c,c∈R}B={(X,Y)|X2+Y2=R2,R>0}这时A∩B有多少个 2020-12-23 …