The problem had become _____ in his mind, and he could not decide what to do about it.
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.
______, I think, and all the problems could be settled.