Jack, look! Everybody is doing homework quietly. ________ you make a noise in class?

 Don't use water to put out the fire if oil catches fire. As is known, oil ________ float on water.

 --Listen! Marry is singing in the next room. -- It __   ___ be Marry. She has gone home.

---- Amazing ! You       wear slippers at work . ---- Don’t you know it’s a fashion ?

—Guess what; Yang Yang failed in the maths test .—How         it be？She is second to none in maths.