The girl _____ black is my sister.[ ]

Would you like another cup of tea?–No, thanks. I ________ be off now. Rose is waiting for me.

This skirt is too _______. Would you show me another one? —OK. Please try this one. It’s cheaper.

________that China has the largest number of iphone4s users now.— I believe so.

What _____ are you doing ? —I’m looking for my book.[ ]