—Hey, can I ask you a favor?—Sure, ________
.—It’s a long time since I saw my brother.—Why ________ him this weekend?
—Would you mind closing the window to keep out the noise?—________.I’ll do it right away.
There are about ______ people in the park on National Day.
We found ______ very difficult for the children to understand what the chairman said at the meeting.
.________ useful book is helpful to ________ artist.