The professor put forward three issues, none of _____ we had ever done any research into before.
Can you make any sense _______ what this writer is saying?
I don't of your sending your daughter to Britain to study,because she is too young.
Have you ever met with this case in your life you can't understand others even if they have said something several times?
In copying this paper , be careful not to _______ any words.
She felt herself _______ by her friends.