Our math teacher is very kind ______ he looks very serious.

---  ___  do you like dolphins? ---Because they are very smart.

Basketball has a history of nearly 300 years. Today it is still loved by______ the young___the old.

---I am going to Nanjing and stay there for a week. ---_________you are there, would you please buy some books for me?

 — Can you tell me ______ it is from here to the Summer Palace?— Let me see. It's about 15 minutes' ride.