do you walk your dog a week—Less than three times a week.

Excuse me. Are these Mary’s exercise books— Sorry. They are exercise books. are on the teachers’ desk.

下列各句中没有语病的一句是（ ）

I’d like to buy a house — modern, firm, comfortable, and ________ in a quiet neighborhood.

Some of the rubbish, such as wood, paper and iron,_____ away over a long period of time.