It is necessary that the students ____ more excercises to do.

Great as Newton was, many of his ideas ____ today and are being modified by the work of scientists of our time.

As ____ clear from his manners, he is a teacher.

____ before we depart the day after tomorrow, we should have a wonderful dinner party.

He concluded his speech with a remark that failure ____the mother of success.

Every means ____ tried out but never with success, as far as my knowledge goes.

____ what may, we’re not going to make any concessions to his unreasonable demands.

____ is no reason for discharging her.

___ will Mr. Forbes be able to regain control of the company.

One of the requirements for a fire is that the material ____to its burning temperature.