A survey of the opinions of experts ____ that drinking a glass of hot milk before going to bed helps one sleep well.
—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
The teacher will never have Tom away within the exam.
The two sisters are ________ different in character --- one talks a lot while the other is a girl of few words.
He has been in bed ______ he fell off his bike a week ago.
The letter he had been looking forward to________at last this morning.