—Recent pressure at work may ______ his behavior.
Scientists think they have _____ in their attempt to find the causes of some major dieases.
If you ever have the _____ to go abroad to work, you should take it.
Carl wanted to play a joke on Bob but gave himself _____ by laughing.
As he had no friends and relatives in the town, the traveler tried to find a _____ somewhere.
The thieves _____ him _____ in the park, took his wallet and escaped.