I cannot open my case.
I have lost my keys.
I did not know that I had to pay.
I cannot find my porter.
Excuse me, sir, that seat is mine.
I cannot find my ticket!
I have left my gloves (my purse) in the dining car.

The noise is terrible.
Did you not get my letter?
I cannot sleep at night, there is so much noise.
There are no towels here.
The sheets on this bed are damp.
I have seen a mouse in the room.
These shoes are not mine.
The radiator doesn’t work.
This is not clean, bring me another.
I can’t eat this. Take it away!
The water is too hot, you are scalding me!
It doesn’t work.
This doesn’t smell very nice.
There is a mistake in the bill.
I am lost.
Someone robbed me.
I shall call a policeman.
That man is following me everywhere.
There has been an accident!
She has been run over.
He is losing blood.
He has lost consciousness.
Hopefully you’ve never been in a situation to have such phrases at one’s ready disposal. Much more from Futility Closet at the link above. Ces chaussures ne sont pas à moi.