--Can Tom help me with my Physics? --His Physics is ____________ yours. He failed the exam, too.
The doctor will not perform the operation ___ it is absolutely necessary.
Difficulties are nothing ___ we are not afraid of them.
―When do we need to pay the balance ? ― September 30.
I'd like to go swimming ____ the water is not too cold.
It’s quite me why such things have been allowed to happen.