As is known to us, theory is based on practice and _____ servers practice. A. by chance B. in turn C. in return C. by turn
________ houses were destroyed in the earthquake.
Li Na officially announced his retirement on September 18, 2014, ________ tennis for 26 years.
You should avoid _______ for your class.
There ______the school bus. Hurry up!
Nowadays, how we can take good care of _______old is becoming _______hot and serious topic.