4.35 'let'
'Let' is used in imperative sentences in four different ways:
* it is used to give an order or instruction
* you use it followed by 'us' when you are making a suggestion about what you and someone else should do. 'Let us' is almost always shortened to 'Let's'
* you use it followed my 'me' when you are offering to do something
* in very formal English, it is used to express a wish.