Listening to loud music at rock concerts _________ caused hearing loss in some teenagers.

From space, the earth looks blueThis is about seventy-one percent of its surface is covered by water

Would you like to go hiking with usthis Sunday? —Sure, _______ I am busy.

Helen is my friend. She is in ______ at Beijing No.11MiddleSchool.

Does your Dad quit smoking, Jenny?— Yes, but he ____ for almost ten years[ ]