细胞外消化
参考答案：
细胞动物的食物由消化管的口端摄入在消化管中消化叫做细胞外消化。细胞外消化可以消化大量的和化学组成较复杂的食物，因而具有更高的效率。
— The woman biologist stayed in Africa studying wild animals for 13 years before she returned.
— Oh, dear ! She ______ a lot of difficulties !
A．may go through
B．might go through
C．ought to have gone through
D．must have gone through
卧式（）壳管蒸发器，制冷剂在管外空间气化，载冷剂在管内流动
