The theory he had stuck _______ to be true.
John, look at the time. ____ you play the piano at such a late hour?
---In the countryside you can enjoy fresh air, blue sky and quiet surroundings.---_______ more and more retired people are escaping from the crowded city.
The police ______ the stolen jewellery and returned it to the owner.
____the problem of land erosion(侵蚀) getting more serious, the government is searching for a way to deal with it.
---How could you be so rude as to walk in here in the middle of my class?---_____________