问：补充250中的34

34.         To read of Abigail Adams’ lengthy separation from her family, her difficult travels, and her constant battles with illness is to feel intensely how harsh life was even for the so-called aristocracy of Revolutionary times.

(A) To read of

(B) Reading about

(C) Having read aboutfficeffice" />

(D) Once one reads of


(E) To have read of


答案A中的of 何用？