引起流行性出血热早期休克的原因是（）
A.大出血
B.电解质紊乱
C.酸中毒
D.血管通透性增加使血容量下降
E.严重感染
参考答案：D
订货的经济批量大小与订货提前期的长短没有关系。 ( )
— What happened to the heroes at the end of the book?
— All of them _____ escape from the enemy's prison and began their new life. [ ]
A. tried to
B. managed to
C. wanted to
D. did their best
