In recent years, some people are heading to Gansu Province for the north-western desert scenery while others are     16     by the Mogao Grottoes(莫高窟) in Dunhuang. There are nearly five hundred caves with huge Buddhist sculptures(雕塑) and fantastic paintings at Mogao. The building on caves ended about 800 years ago and gathered the     17     of countless Chinese craftsmen. The caves are important for understanding the ancient cultures of north-western China. Visitors are only     18     in from 8 a.m. to 6 p.m. The limit is necessary, for too many visitors will bring large amount of CO₂ to the cave. That will have a bad     19     on the Grottoes. Please follow the website of online booking to learn more details.

Why do people use dictionaries? Three ways make dictionaries useful: They show us how to spell words; they tell us the meaning of words; they show us how words are used with other words to make people understand     20     what we want to say or write.

This dictionary does all things above with a bit more than 3,000 words. It not only gives the meanings of words in an easy form, but also shows how the words are used by using the words in     21     chosen sentences.

If we want to look up the meaning of a word, it will not help us if some unknown words are     22     in the explanation. So, in this dictionary, a fixed list of about 1,500     23     words are used to explain all the words in the book. For example, ‘friendly’ and ‘friendship’ are explained with the sentences made from ‘friend’. This list of words will be found at the end of the book.