单项选择题

It Was not until I had read your last 1etter that l understood the true state Of the sad fortunes Of his family.

A.还没读你最后一封信,我就知道了他家遭受的惨况的实际程度。
B.那是在读完你最后一封信后,我知道了他家的不幸遭遇的实际状况。
C.我终于读到了你的最后一封信,从信中得知了他家遭受的惨况的实情。
D.直到读了你最后一封信,我才知道了他家遭受的惨况的实际情形。