根据四舍五入法，可以把29.8看成30，3.01看成3，所以29.8×3.01≈30×3．
故选：C．
—What is your teacher like?
—_____ [ ]
A. He likes teaching.
B. He is like a friend.
C. He is strict but nice.
D. Vegetables and fruit.
计算二重积分
，其中D由y=x3，y=1，x=-1围成f是一个连续函数，则I的值为______．
，其中D由y=x3，y=1，x=-1围成f是一个连续函数，则I的值为______．