the factis ____ he doesn't understand english at all.a.what b.it c.which d.that

the factis ____ he doesn't understand english at all.a.what b.it c.which d.that
the factis ____ he doesn't understand english at all.a.what b.it c.which d.that

the factis ____ he doesn't understand english at all.a.what b.it c.which d.that
d.that

表语从句，主语 + 系动词 + that从句。例如：
The fact is that we have lost the game. 事实是我们已经输了这场比赛。