I haven't see An for ____ long that I've forgotten what she looks like.A.such B.very C.so D.too

I haven't see An for ____ long that I've forgotten what she looks like.A.such B.very C.so D.too
I haven't see An for ____ long that I've forgotten what she looks like.
A.such B.very C.so D.too

I haven't see An for ____ long that I've forgotten what she looks like.A.such B.very C.so D.too
C.so
SO THAT 从句 如此以至于