You 'd better do it yourself 的yourself前不加by吗?

you'd better not do it..能说成you'd better don't do it.或者you'd better do not it.为什么? you'd better It's better 后面分别加什么?do or to do? You'd better( )it today You'd better( )it today? You are old enough,boy.you'd better do it ____(you). You'd better +do 还是 to do? You'd better know You'd better know it you'd better not do it again!--能这样改吗：you'd better don't do it again!-----------------------------------请说明为什么,谢谢（能不能都请说明） You'd better do it by yourself.____ else can help you.A.somebody B .Everybo YOU’D BETTER DO IT NOW请问这个‘D是 WOULD 还是 HAD You should ________ it better next time.A.do B.did C.to do D.not do You 'd better do it yourself 的yourself前不加by吗? You'd better do it ( )your mother didas?like?when?because? You'd better do it __ your mother did .a.as b.like You'd better do it _ your mother did .A.as B,like 应该选哪个 you‘d better do的意思是什么? you'd better _(do) more exercise you'd better not do还是You'd better not to do