以下哪项不是急性肠系膜上静脉血栓形成的主要因素（）。
A.门静脉高压症
B.腹腔内感染
C.真性红细胞增多症
D.心房纤颤
E.口服避孕药
参考答案：D
_______ the difficulty that he has supporting his big family, he still makes every effort to realize his dream, which I believe is __________ his reach.
A．Despite; within
B．Though; beyond
C．Though; within
D．Despite; of
