Can I go to the park, Mum?—Certainly. But you ______ be back by six o’clock.
________spending our vacation in a noisy crowded city,why not try hiking in the country?
The city is famous _______ its fine parks. [ ]
_____ did Prince William’s wedding (婚礼) last? — It lasted for about 5 hours.
________ is this pen? — It’s white.