题目

As they _____ in the snowstorm in the deep mountains, they had great _____ in getting in touch with the outside world.    A. lost; trouble   B. were caught; difficulty   C. were stuck; difficulties D. were trapped; troubles   答案：B生物的性状包括A.生物的形态结构特征B.生物的生理特征C.生物的行为方式D.ABC都是