Cancer has become the top killer ________ I think threatens the health of millions of people.

John learn French and Spanish at the university. He is good at French, but can’t speak the fluently.

____ the crisis of economy getting more and more serious, the government is searching for ways to improve people’s life.

Elizabeth believed the dog would die if _____ to her cruel owners so she kept it

Did they attend the opening ceremony? —They _, but they were late and quit it.