It is really _______ unusual experience, and I’ll never forget _______.

The rivers will become dirtier and dirtier ______ wetake action to protect them.

Mr.Smith, ofthe speed,started toread a novel.

30He insisted on going abroad to have further study ____ his parents objection

171. You should put down your jacket, otherwise both of you will have a quarrel. That will make things worse. The underlined part probably means _____.