At the very heart of Beijing，the Palace Museum is China's largest of all the ancient
（building）.
The poor （home） boy often did his homework in the street by the light of a restaurant．
Nothing is （possible） if you set your mind to it．
If more people give up （drive） cars， the air will get much cleaner．
To achieve our dreams， we must take every life choice （serious）．
There are many （different） between the twins． One is shy， but the other is outgoing．