Look! A book is on the floor. Whose is it?—It ______ be Rick’s. It has his name on it.

Linda felt very_________ after the long way, so she stopped to have a rest.

Kim, I haven’t seen your mother for so long, where is she? —Oh, she ________________ England to learn further studies(深造). She left a month ago.

Realizing ______ I had been able to accomplish, my fears of failure grew rapidly.

He will never give up________difficulties he has.[ ]