lt is necessary that train yourself before the walk

lt is necessary that train yourself before the walk lt is necessary to study hard at school.同义句 we think that is necessary还是we think that it is necessary 求find it necessary和lt is necessary的解释首先为什么find it necassary里不加is呢?两个necessary的词性一样吗? it is clear that sleeping is necessary to everyone is it necessary to tell his father everything?此句用is that necessary If he is also that into me.If necessary是什么意思 we consider____the machine should be adjusted each time it is usedA.that it necessary B.necessary it that We consider _________the instrument be adjusted each time it is used.选项:a、that it necessaryb、it necessary thatc、 necessary thatd、necessary of it that 17. We consider the machine should be adjusted each time it is used.A. that it necessary B. necessary it that C. it that necessary D. it necessary that解析下! lt is single that l have known all the lt is known that smoking does great ----[harm]to us. 英翻中：Modern medicine is developing so quickly that it is necessary for doctors to keeplearning government is a necessary How () is that pen?lt is ()yuan.l'11 take it .The schoolbag is very nice. we consider__ the instrument should be adjusted each time it is used.A,that it necessary B,it necessary that.答案选择A,为啥B不对? we consider____the machine should be adjusted each time it is usedA.that it necessary B.necessary it that 选什么?为什么?B选项错了，应该是it necessary that 对不起哦 i think it is necessary that. and that.这样用有错吗,第二个that是不是要去掉?