Could/can

[Rachel Adams]

When talking about a specific situation "can" isn't used as in my first example. "Can" is used in general situations as I have learnt, for example, "Earthquakes can be very dangerous." But in this sentence when talking about what is generally possible is it wrong to use "could" "may" or "might"?

1. "Someone's at the door. It could/may/might be my sister." Not "can".

2. "Earthquakes could/may/might be dangerous."

 

[GoesStation]

1. "Someone's at the door. It could/may/might be my sister." Not "can".

They're all possible. I'd most likely use "might".

2. "Earthquakes could/may/might be dangerous."

They're all odd. We know that severe earthquakes are dangerous, so only can really works.

 

[Rachel Adams]

They're all possible. I'd most likely use "might". They're all odd. We know that severe earthquakes are dangerous, so only can really works.

Do you mean that in the first example "can" also works? I think in Raymond Murphy's "English Grammar in Use" I read that "can" is the only correct option when we say what is possible in a particular situation. Is in AmE either "may", "might" "could" and "can" a correct choice?

 

[jutfrank]

In 1, can is not correct.

In 2, only can is correct. The others are wrong.

 

[Rover_KE]

1. "Someone's at the door. It could/may/might be my sister." Not "can".

However, you could use can't.

'Someone's at the door. It can't be my sister – she's in jail'.