(2012·辽宁高考)One of our rules is that every student ________ wear school uniform while at school.

—I wonder why Mr Green hasn't showed up at the meeting yet.—I'm not sure，but he________in a traffic jam driving here.

— Where is my dictionary?— You ______ it in the wrong place.

 If I went to the moon, I ______ bring something unusual back to the earth.

 －Are you coming to the English evening?－I’m not sure. I     go to the concert instead.