[Grammar] It's been raining for three days.

[beachboy]

It's been raining for three days.

How strange would it sound if one said "It's been raining since three days ago"? Is it bad English, or just unnatural?

 

[emsr2d2]

It's grammatically correct but it's very unnatural. There's nothing wrong with "It's been raining since" but we would usually follow it with the name of a day (or a time).

 

[tedmc]

It's been raining for three days.

How strange would it sound if one said "It's been raining since three days ago"? Is it bad English, or just unnatural?

It is simpler to say: it has been raining for three days.