let a,b and c be rational numbers and b=5分之12-5分之13a,c=5分之13-5分之12a,then a的平方-b的平方+c的平方

Let Ben and Tom ( )good friends.A is B are C be D will be ( )Let john and jack______our friends.A.be B.to be C.are D.is Let me introduce my sister____you.A.to B.for C.and D.be 证明1.Let A,B,and C be sets.Prove thatA∪包含 (A∪B ∪C).2.Let A,B,and C be sets.Prove that(A-C)∩(C -B) = 空集 let a,b and c be rational numbers and b=0.24-0.26a,c=0.26-0.24a,then a^2-b^2+c^2= let a,b and c be rational numbers and b=0.24-0.26a,c=0.26-0.24a,then a^2-b^2+c^2= cat( )rat A:chase B:chasing C:chased Let a,b and c be ration numbers and b=12/5-13/5a,c=13/5-12/5a.then a2-b2+c2=? Let you and _____good friends.A.I am B.me be C.me are D.I are(选择 Let is ( )pen friends.A:be B:are C:is Tom,Let,s play__that ball.A.with B./ C.and Let us ____good friends and always help each other.A.to be B.are C.be D.get回答写理由快 一.三个互不相等的有理数,即可分别表示为1,a+b,a的形式,又可分别表示为0,a/b,b的形式,则a^2000+b^2001＝?二.Let a be integral part of 根号2 and b be its decimal part.Let c be the integral of π（派） and d be the decim let a,b and c be rational numbers and b=5分之12-5分之13a,c=5分之13-5分之12a,then a的平方-b的平方+c的平方 又是一道英语的数学题.let a,b and c be rational numbers and b=12/5-13/5a,c=13/5-12/5a,then a²-b²+c²=—— Supper__ ready and let's go and have___ A.may be,supper B.is,it The book is borrowed from the library .You ___your children put dots andlines here and there.A.shouldn’t be letting B.needn’t have let C.ought not to have let to D.mustn’t have let为什么 Let us -----good friends,shall we?A to be B be C are D being