Learn English – The usage of “must be”

auxiliary-verbstense

I saw a sentence "there might be a new smartphone released this September" in some context, then wondered if I could just replace might by must here, i.e.

There must be a new smartphone released this September.

I think it is a little bit strange of using the "be" of "must be" as the "be-verb" used in "passive tense", but not sure whether it is right or not.

So later I added the "been" in the sentence. i.e.

There must be a new smartphone been released this September.

I think it might be grammatically correct, since its structure is the duplication of the structure of "There must be some mistake."

So I wondered if one day the fact is that one company didn't release any new cellphone this September, but some guy just somehow didn't believe it, then could he just shout out loud "There must be a new smartphone been released this September!!!!!!!" as a grammatically correct sentence?

Best Answer

First off, phrases like this September are almost always used to indicate something in the future. The original sentence is speculating about a possible future event. To refer to some September that is in the past, you would say this past September or last September.

Since this September refers to the future, it is not appropriate to use the phrase must be. Must is usually used to talk about the past, as in “The plane must have landed by now”. It can also be used to make an a guess about the present, as in “You must be joking”, or to define a rule of some sort, as in “The toys must be put away before snack time”. The only appropriate use of the word must in talking about the future that I can think of is something like “They simply MUST release a new phone this September, or I will be very angry!” But there is no be-verb associated with must in this case, so it’s different than what you’re talking about.

So, to use must be in this sentence, you would have to either be making a guess about the current release of the phone (“They must be releasing the phone right now, if only I could watch the announcement!”) or talking about the past (“There must have been a new smartphone released last September”). That last sentence sounds a little awkward to my ears, though. The better phrasing would be “They must have released a new smartphone last September”.

Your last sentence is not correct because you:

  1. Used must be to talk about the past (be is present tense)
  2. Used two different be-verbs (be and been) to talk about the smartphone.
  3. Used this September to talk about the past

Hope this helps!

Related Topic