______ you ever wondered how Valentine’s Day started?

Are chemicals responsible ______ increased leukemia rates?

While the ship ______, the stern broke in two.

Many respondents did not provide ______ answer to question 4.

Directions: One underlined word or phrase has an error. Correct it. New York inventor Charles Fritts has created the first solar cell in 1883. Since then, other scientists have made many advances in solar technology.

Minor collisions between ships and icebergs ______ still common today.

Explorers ______ the wreckage of the Titanic in 1985.

Past Tense / Past Progressive

Directions: One underlined word or phrase has an error. Correct it. The European Union introduced the euro in 1999, and it was becoming common currency in 2002. Before 1999, people used different currencies.

Can parents treat all their children ______?