Most people here have been quoting song lyrics which are over-colloquial by educated usage standards. I should like to quote a line from a slightly archaic version of Blow Away the Morning Dew that is so magnificently grammatically correct that you have to laugh in admiration:

There is a flower in yonder field
That's called the marigold
And if you will not when you may
You shall not when you would

You'd have a job instilling such nice use of English verbs to kids on a modern GCSE course!