It is required in the library regulations that any book borrowed __________ by due time, or the borrower will be fined.
On top of the mountain ______, which was built 2,000 years ago.
______ to get a ticket for the concert Eason's Life, George has been standing in a queue for 3 hours.
With the development of high technology, more and more new things ______ in the past years.
That e-book is no larger than an ordinary book with a screen ______ you can read original book and film reviews.
It was very lucky to see the "Monster of Lake Tianchi", ______ we didn't see it clearly.