I’ve been working for over twenty years and seldom so tired as now .
The freezing point is the temperature __________ water changes into ice.
Don’t talk about such things _______ you are not sure about.
Hurry! The train _______. You know it _____at 8:30am. .
With the help of high technology, more and more substances _________ in the past years.
Jim is the only one of the policemen in his office who __________ the award.