委婉请求 Could I...May I...我能.(后跟动词原形）How about/What about...做某事怎样?（后跟动词的ing形式）What's your opinion?你的意见是?How do you like it?=What do you think about it?=What do you think of it?你觉得怎样?
给别人提建议,可以说Maybe you should...也许你应该.（动词原形） Perhaps you could...也许你能.动词原形
You'd better...你最好...（动词原形）Why not=Why don't you...为何不.（动词原型）I think you should/could/must我觉得你应该/可以/必须（动词原形） Let's...让我们...（动词原形） 或者直接使用祈使句,例如I think you should go to the hospital我认为你应该去医院=Go to the hospital.