So many people violate traffic regulations that we ____ put too much emphasis on the importance of traffic safety. 

— It’s hard to believe that Jack ________ have fought with the policeman.— Yes. If one ________ ask for trouble, it can’t be helped.

—Hi，Joan.Any idea where Tom is?—He ________ on the playground.I saw him there playing football just now.

 He had no choice but to go on because it is their agreement that no one ______ quit the plan half way.

He ______ it on schedule, but somehow he fell behind.