Professor Johnson is said _____ some significant advance in his research in the past years.

The three men tried many times to sneak across the border into the neighboring country_____ by the police each time.

_____enough time and money, the researchers would have been able to discover more in this field.

The Clarks haven’t decided yet which hotel _____.

_____, he can now only watch it on TV at home. 

_____ no cause for alarm, the old man went back to his room.

In international matches, prestige is so important that the only thing that matters is to avoid _____.

_____ time, he’ll make a first-class tennis player.

This missile is designed so that once _____ nothing can be done to retrieve it.

He resented _____ to wait. He expected the minister _____ him at once.