【请教八年级（上）英语寒假作业中几道难题：1.-Listen!IsPorfessorJohnsongivingareportinthehall?-No,it____behim.HehasgonetoJapan.A.needn'tB.maynotC.mustn'tD.can't2.Theteacherhasalreadytoldmeb】

　　请教八年级（上）英语寒假作业中几道难题：

　　1.-Listen!IsPorfessorJohnsongivingareportinthehall?

　　-No,it____behim.HehasgonetoJapan.

　　A.needn'tB.maynotC.mustn'tD.can't

　　2.TheteacherhasalreadytoldmebutI'mstillnotclear____todonext.

　　A.howB.whatC.whyD.interest

　　3.Mindyoursteps,boy!Don'tyouseethewords“____thegrass"

　　A.KeepoffB.KeepoutC.TakeoffD.Takeout

　　4.Allofusfind____necessarytotakeexerciseeveryday.

　　A.thisB.thatC.itD.them

　　5.Idon'tlikethetrousers.Pleaseshowmeanother____.

　　A.pieceB.pairC.oneD.ones

　　6.Idon'tthinkit____.

　　A.matterB.doesmattersC.mattersD.ismatter

　　7.____beautifulsunshinewehave!

　　A.howB.HowaC.WhatD.Whata

　　8.Anndrew____horseontheblackboard.

　　A.veryaniceB.quietaniceC.aquiteniceD.verynicea

　　9.Lucycan'thelpTomtomend____bike____.

　　A.her;himselfB.him;herselfC.his;herselfD.her;herself

　　10._Ilikestrawerriesverymuch.

　　-_____

　　A.SodoesGinaB.DoessoGinaC.SoGinadoesD.Ginadoesso

　　这些题目的答案我全都知道,请给出解析和考点