Verb Tenses

Correct the sentence: Thomas works at Harvard University since 1989.

Harry always visit his cousins at Christmas.

Neither Freddie nor his friends studying their lessons.

Several tourists buys souvenirs. Options: NO CHANGE, buying, to buy, buy

The Black Plague treats by physicians during the 19th century.

A diary finds by Marie last night at the park.

Many books reading by scholars last night.

A number of workers protesting in front of the factory.

The Louvre Museum visits by many tourists every year.

While I clean my room, the doorbell rang.