Historically, ________ main material for making tables has been wood, but ________ metal and stone have also been used.
—He _____to the meeting. Have you informed him of it? —Sorry. I______to.
It is not enough only ______the rules of grammar if you want to learn English well.
He ______the person referred to be put in prison.
______you I owe a thousand apologies ________having doubted your ability.
______at in this way, the present situation about birds flue doesn’t seem so disappointing.