半径是5分米．
圆的周长：
2×3.14×5，
=3.14×10，
=31.4（分米）．
答：这个圆的周长是31.4分米．
—Let's have hamburgers for breakfast.
—_____. [ ]
A. That sounds great
B. Yes. Let's do
C. Let's have eggs
D. No, I don't like hamburgers.
根据GB8076混凝土外加剂检验时，所用砂的细度模数应为（）。
A.大于2.3
B.2.3~3.0
C.2.6~2.9
D.小于3.0
