Is air the lightest thing in the world– Not .Scientists from Zhejiang University have just developed the world’s lightestmaterial.

Ask them their names and ____________,please. — OK. Mr. Zhang. I’ll do it right now.

Lily and I are in ______ grades, but we are good ______.

They no longer have to ______ large numbersof temporary workers to do the harvesting.

We can do the work better with ________money and _______people.