lt is necessary to study hard at school.同义句
问题描述：
lt is necessary to study hard at school.同义句
答
To study hard at school is necessary .
答
you are necessarily study hard at school.
答
You must study hard at school
答
It is a must to study hard at school .
答
1.to study hard at school is necessary.2.studying hard at school is necessary.3.you are supposed (outght to) to study hard at school.不知道你的同义指的是句式变换还是用词变换啊.
答
To study hard at school is necessary .( 动词不定式作主语）