1.I will go to bed after I finish my homework.(同义句)---I will sleep after I finish my homework.
2.You needn't finish your homework now.(同义句)---You don't have to finish your homework now.
3.He often talks a(bout) his family and he says he loves his wife and children very much.
4.They both study very hard.(同义句) ---They two study very hard./Both of them study very hard.