已知四棱锥P-ABCD的三视图如下图所示,则四棱锥P-ABCD的四个侧面中的最大的面积是( )
A:3
B:25
C:6
D:8
形成尿液的基本单位是( )
Organic farmers, ____(因此), often prefer using natural waste from animals as fertilizer.
pH
2
4
6
8
10
12
颜色
红
粉紫
蓝紫
绿青
草绿
黄
将紫甘蓝汁加入与胃液的pH相当的溶液中,呈现的颜色为何?( )
There ____ (be) few students playing in the playground because of the coming exam, will there?
结合语境解释下面句子中的划线词语有误的是( )