The important thing to keep in mind is that when you’re writing, choose one version and stick to it.
|Past actions with result now||Use present perfect
I’ve lost my mobile phone. Have you seen it?
|Use present perfect or past simple
I’ve lost my cell phone. Have you seen it?
I lost my cell phone. Did you see it?
|Using shall||Either will or shall can be used with the first person (I or we)
I will/shall be late to the meeting because my car’s broken down.
Shall can be used to ask for advice.
Which version of the report shall we use?
|Shall is unusual
I will be late to the meeting because my car’s broken down.
Should is the more usual way to ask advice.
Which version of the report should we use?
|Can’t vs must not||UK English users use can’t to say that they believe something is not probable.
I haven’t heard from David. He can’t have got my message yet.
|US English uses must not when something isn’t probable.
I haven’t heard from David. He must not have got my message yet.
|The all important weekend||At the weekend/at weekends||On the weekend/on weekends|
(note: Indian English often uses fill up – it’s not wrong, just different)
|Use either fill in or fill out||Use fill out|
|Round||Use either round or around.
He turned round/around.
He turned around.
|Front/back||Use at the front or back
Please sit at the front of the room.
|Use in the front or back
Please sit in the front of the room.