一般公认中午的日光是理想的参照光源，并把它的显色指数定为（）。
A.1
B.10
C.0
D.100
参考答案：D
分类是学习化学的方法之一，下列物质是按单质、盐、混合物的顺序排列的是
A．氧气、碳酸钙、空气
B．氢气、硫酸钠、水
C．甲烷、食盐、冰水
D．金刚石、熟石灰、石油
You were stupid to climb up that big tree. You ______ yourself.
A．must have killed
B．can have killed
C．should have killed
D．might have killed
