How long may I _________ the book? —For two weeks.

About _________ of the teachers in tour school were born in ________.

The fact has worried the people across the world ___________ the earth is becoming warmer and warmer these years.

TV and computer are so popular these days.——Yes, they can ____ our eyes to the outside world.

Did you meet the professor at the airport?—No，he ____ by the time I ____ there．