I found the professor's lecture quite difficult to follow because it ___________ when I arrived.
A.started B.was starting C.would start D.had started
—Hi, let’s go swimming.
—Sorry, I’m busy right now. I ___________ in an application form for grad school.
A.fill B.have filled C.am filling D.will fill
the course very difficult, she decided to move to a lower level.
A.Find B.Finding
C.To find D.Found
Volunteering gives you a chance _______ lives, including your own.
A.change B.changing
C.changed D.to change
There are still many problems ______ before we are ready for a long stay on the Moon.
A.solving B.solved
C.being solved D.to be solved
The park was full of people, ________ themselves in the sunshine.
A.having enjoyed B.enjoyed
C.enjoying D.to enjoy
