Smoking pollutes air. You ______ smoke here.

Jack ________ have fought with the policeman. —Yes. If one ________ ask for trouble, it can’t be helped.

—How was your trip to Yancheng last week?—Wonderful! I only felt sorry that I ________ the nature reserve of red­crowned cranes, but the weather was awful.

 It was the order that all the soldiers ________to the front.

I wish I ___ able to tell him all about it last night.