All students in the class_______ a loud laugh when the professor told them a joke.

There are a lot of computers in the lab,and they need professional __________ to make sure they can be in a good state.

Adolescents are warned not to ____________ their pimples in case they get scars.

 The small village has _____ a town.

My grandfather, who          the World War Two, likes to talk to us about his experience.