No matter what changes have taken place, nobody can _______the fact that the experiment is a great success.[ ]

When the man walked _______ the library, he found a cat at the corner.

wonder why he has been acting so strange these days. — Recent pressure at work may ________ his behavior. [ ]

________a certain doubt among the people as to the practical value of the project

By the time he retires, professor Baker _____ foralmost forty years．