It was a serious mistake, ______ caused by carelessness.

Mr Smith __________in London for a few years before he _____to China.

The girl ______ red plays the piano well. She is often invited to give performances by TV and radio stations.[ ]

How many students in your school have lunch at home? — Only ________ of us have lunch at home.

What color is it? — It’s _______ orange. It’s _______ orange pen.