What do you think of teaching, Bob?—I find it fun and challenging. It is a job ______ you are doing something serious but interesting.

In recent years much more emphasis has been put______ developing the students productive skills.

My little sister saw _____outside. Shall we go and have a look

She ________a German. She has _______him for three years.

Tom’s father had not spoken to him since his marriage, because he considered Tom ______ a mistake in marrying so young a girl.