The notification of the airport is a kind of obligation announced by the judicial authority. So why not say, “Liquids must be in 100 ml containers.” I would say that “could” in this sentence expresses more competence than permission. You could hear a phrase like this in speech, but in theory, the right set of words is “you could allow me” and in writing, it should be divided into two sentences. I`m afraid you`re a little more specific. Can you provide a sentence that disturbs you? We are happy to comment. We often use boxes to ask for and give permission. We could ask permission (but not to give it), but what can you say about this sentence: “I didn`t know you were the principal of the school in this office, you could allow me to talk to you?” Tell me more about how to use it could be in this sentence and whether the sentence is grammatically correct or not. What can COULD express here? Hallow , again I need some clarification on the use twice in a sentence This sentence would generally be understood as an external obligation – from teaching, course, school or teacher. However, a spokesperson may feel compelled to place an order. For example, I have to give up this task tomorrow.
Otherwise, I don`t have time for other tasks. In this example, the obligation itself is imposed. But in the absence of information indicating that the engagement in the sentence you mentioned would normally be considered external.