牙本质所含无机物约占重量的（）
A.50％
B.60％
C.70％
D.80％
E.90％
参考答案：C
城市气温要比郊区高，这就是“（）”效应。
— The dish is delicious!
— Well, at least it's ________ the one I cooked yesterday.[ ]
A. as bad as
B. no worse than
C. as well as
D. not better than
