用“介词+关系代词”填空。 1. They were sure to visit the town after the flood, the location _______ was little known. 2. I come from the Seattle area, ________ many successful companies such as Microsoft and Boeing are located. 3. He paid the boy $10 for cleaning ten windows, most _______ hadn’t been cleaned for at least a year. 4. Rachel, ________ she placed the greatest trust, failed to match her expectations. 5. Her son ________ she was so devoted, went to New York two years ago. 6. Hank didn’t tell his parents about the incident, ________ I was very grateful. 7. She has now moved back to the house ________ she was born. 8. In the novel by Peters, ________ the film is based, the main character is a teenager. 9. There are still many things in our solar system ________ we know nothing. 10. Government reports, legal documents and most business letters are the main situations ________ formal languages are used.