Could you tell me ______ it takes to go from here to Beijing by air? —About 50 minutes.[ ]

.－Who taught _____ to swim?－I learned it by _____.

Can you remember when Mr. Green left _____ city?—Sorry, I can’t. I only remember it was _____ Monday.

Can I go to the park, Mum?—Certainly. But you ______ be back by six o’clock.

There is______ old football under ______ bed. I like to play ______ football.