Research findings have shown that about 20 percent of people only 10 percent can be ____(分类) as “early birds”.
在半径为r的半圆内作一内接梯形，使其底为直径，其他三边为圆的弦，则梯形面积最大时，其上底长为（ ）
—______ does your cousin usually go to work on foot?—He says it's good for his health.
菜____ 味____ 昨____
来____ 未____ 作____
