Learners' Questions: Using 'let's' and 'it's high time'

Abdalla in Egypt asks: which is correct: 'let's go home' or 'it's high time we went home'? Dan has the answer.
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Transcript
Hi guys! Dan for BBC Learning English here with this week's Learner Question. Find out what it is after this.
OK! This week's learner question comes from Abdalla in Egypt, who asks, 'which is correct: let's go home or it's high time we went home, and why do you use the past tense of 'go' here?'
It’s a good observation, Abdalla, and a good question. Well, both of these sentences are correct in their grammar and their meaning, but they’re different.
Let’s is let us. And it’s followed by the bare infinitive, which is a verb without to. Unlike the verb let, which means 'give someone permission'. Let us is used as a gentle suggestion. For example,
let’s go to the cinema, or, let’s not have Chinese for dinner tonight.
It’s often combined with the question tag…shall we? For example, let’s go to the cinema, shall we?
It can be used as a gentle imperative, or command to do something but it really depends on who is talking to who, and the context and their tone of voice. For example, two friends might say to each other: Let’s go to the cinema, shall we? That’s a suggestion. But a parent might say to a child: Let’s be quiet, shall we? That’s not a suggestion.
The other phrase you asked about is it’s high time we went home. And this is a subjunctive, that’s why we use the past form of the verb and not a different form. It means it’s a kind of unreal situation like a conditional. For example, it’s high time we ate something!
We use this structure to mean that something should have already happened by now. And it’s often used to show irritation – again like a parent to a child, who might say: it’s high time you cleaned your room! I’m sure you’ve heard that one, haven’t you? This means I want you to clean your room.
I hope that answers your question Abdalla. Thank you very much for writing to us. If anybody else out there has a question for Learners’ Questions, you can email us on: [email protected]. Please remember to put Learners’ Questions in the subject box and include your name and the country that you’re writing from. We can’t answer every single question, guys. We just get too many, but we do read all of them. And for more information, go to our website: bbclearningenglish.com. That’s it for this week’s Learners’ Questions. I’ll see you next time. Bye.