The water of the Miyun Reservoir is regularly ______ to ensure the security of Beijing people’s drinking water.

I’m quite interested in Spanish history, the civil war in Spain _______.[ ]

“Do you mind doing extra work for your classmates”—“_______. I’m always ready to help others. Which of the following is NOT right

Many species of animals are in danger of ________ due to the pollution these days. [ ]

We often do _______ homework at home.