Tom is very short . So he sits _____the classroom .
— Have you solved your problem?— I’ve kept on thinking about that matter__________, but I have had no idea.
— What's wrong with my son, doctor?— _________. Just a cold.
— _________ did you do with old books?— I sent them to children in poor areas.
— What______useful dictionary for beginners of English! Where did you get it?— I bought it in the bookshop.
— I visited the Purple Mountain Observatory last Sunday.— Why didn’t you tell me earlier?