________ did your uncle leave his home town?.— Let me see. He _______ for nearly twenty years.

Everyone must make a contribution protecting our environment.[ ]

You’re badly ill. You’d better _____ cold water. [ ]

To improve his English,he spends _______ one hour a day listening to English programmes. [ ]

Some people are worrying about the possibility ________ mobile phones could be responsible for a range of illnesses, from rashes(皮疹) to brain tumors．