我国现行的民族自治地方有( )。
A.自治区、自治州、民族乡
B.自治区、自治县、民族乡
C.自治区、自治州、自治县
D.自治州、自治县、民族乡
参考答案:C
He didn’t go to school yesterday ________ he was ill.
A.because
B.because of
C.if
D.so