We’d better not keep the lights______ when we have PEclasses outside.

He has two sons. One is a doctor, ____ is a student. He is now studying at ___ university.

Scientific surveys conducted during the climbs ______that Mount Huandoy in Peru______ 6395 meters high

The supermarket provides customers _____ plastic bags for free.

His first concert was well ____ and so all the tickets of his second one were sold out quickly.