It is the fact he doesn’t know his own birthday surprises us all.
A. which; which
B. that; that
C. which; that
D. that; which
网友回答
A. which; which
(答案→)B. that; that
C. which; that
D. that; which
解析：考察同位语从句和强调句型。同位语从句That he doesn’t know his own birthday解释the fact的内容。第二空that与it is构成强调句型。故B正确。