I know nothing about his journey ______ he is likely to be away

I know nothing about his journey ______ he is likely to be away for six months.
A、except
B、unless
C、except that
D、apart from
【正确答案】：C
【题目解析】：except 除了；unless 除非；except that +从句，表示 除了……；apart from 除了……外题目后接从句，因此C正确句意为：我对他的旅行一无所知，只知道他可能要离开六个月。