下列不属于五行之水的是（）
A.五色之黑
B.六腑之膀胱
C.五脏之肾
D.五体之筋
E.五味之咸
参考答案：D
单句改错。
1. How much percentage of his income is taxable (可纳税的)?
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2. An increasing percentage of the population owns their own cars.
3. The most percentage of the people are against the plan.
设L是圆周x2+y2=4，则对弧长的曲线积分（）。
A．4π
B．8π
C．2π
D．π
（）。