This novel was concerned _____the Second World War, while most teenagers are more concerned _____the hero’s love story[ ]

The chairman thought ___ necessary to invite Professor Smith to speak at the meeting .[ ]

The officer ordered the policeman to _____ that tall man in a black hat. He thought the man might be the murderer wanted.

Miss Wang’s class is very interesting. —________. We all like her class very much.

It has been thirty years since I my hometown.— How time flies! Great changes in our hometown in the last thirty years.