Is this necessary to complete the design before the National Day?为什么是this而不是 it ,that,he?说出详细原因

It is not necessary to do this work```! It is necessary for them to suport each other this sport event.改为同义句It is necessary __ __suport each other this sport event it is necessary for you to work Is it necessary to learn grammer It is necessary for sb to It is necessary to do 的例句 Love is necessary to...是啥意思? To keep healthy is necessary.(同义句) Is( )necessary to tell his father everying?it,this,that三个词用哪一个?为什么?又为什么不用另外两个? This protects your clothes from food or is used to wipe your hands or mouth when necessary This is for your information and necessary action.怎么翻译? Is this necessary to complete the design before the National Day?为什么是this而不是 it ,that,he?说出详细原因 短文改错中This is necessary for the students to get rid off the bad habit 中的 This 为什么改成It 1.this math problem is[ ]that one.A.not so easyas B.more easy than C.as easier than D.easy than2.His friend find[ ] him everything that has happenedA.it necessary B.that necessary to C.necessary it to D.necessary to tell 关于necessary.it is necessary to do sth.it is nec关于necessary. it is necessary to do sth. it is necessary to doing sth. 两者有什么区别?什么时候用to do .什么时候用 to doing?请回答, 英语necessary的问题It is necessary for us to learn.可不可以改成We are necessary to learn The indoor swimming pool seems to be a great deal more luxurious than ( )A is necessary ;B being necessary ;C to be necessary ;D it is necessary is it necessary to tell his father everything?此句用is that necessary