____ the Forbidden City is almost 600 yearsold, _____ it is still very beautiful.

－I want toborrow the book, but I don’t know how long it may ______.－For two weeks.

Our plane will . All the passengers, please your mobile phones.

The problem is ________ sometimes when we are given something on a constant basis, we start to take them for granted and forget being thankful for what we already have

He was so tired that he fell________as soon as he went to bed.[ ]