.----Who are those people gathering in front of the building? -----A group __________ itself the youth volunteers.
It is highly desirable that every effort to reuse the pollution in Beijing.
It is said that Tom’s sister fell off her bike on her way to school, _____ in the left leg.
to his research, he spared no time to spend a weekend with us.
A man is often afraid of .
Mary was not afraid of .