The Great Wall istourist attraction that millions of people pour in every year.
so a well-known
a so well-known
such well-known
such a well-known
He returned from a long journey,________.
Teachers should keep students________a distance,but not ________the distance.
________by his words,all the audience clapped now and then until his address came to an end.
The train went round and was soon________.
It is ________to protect the traditional culture.