Ten years_______ since my uncle ________ to Ningbo.
--- What’s your brother? ---He _______ a teacher, but now he is a doctor.
--- How long have you ________ Hong Kong? --- For two weeks.
Jack ____ to help our Chinese teacher carry books yesterday morning.
---Do you mind if I open the door ? --- ____________.
This kind of CD-ROM is very popular. Why not buy one before it________ ?