to know, it's part of English. Okay, you ought not to keep your phone in your back pocket. Ought not to. You can see not squeezes between ought and to, it squeezed in there, it's sneaky. Like a pickpocket. You ought not to keep your phone in your back pocket. To is optional, you ought not
SHOULD and OUGHT TO - everything you need to know | You SHOULD watch this lesson ;)