--Have you seen Jack? His mother is looking for him all the afternoon.--No, I haven’t. I am sure her mother________be very worried.
Students should learn how ________ problem.
—Why is Linlin practicing speaking English? —________ abroad for further study.
—Why are you so excited today? —We were told ________ a picnic this weekend.
How kind you are!You always do what you can ________ others.
He sat in the armchair, ________ a newspaper.