_____ from endless homework on weekends, the students now find their own activities, such as

taking a ride together to watch the sunrise.     [ ]

A. Freed

B. Freeing

C. To free            

D. having freed

下列关于头痛程度和性质的叙述正确的是（）

A.脑膜刺激的疼痛多为轻度或中度

B.脑肿瘤的疼痛多为重度

C.肌肉收缩性头痛多为电击样痛或刺痛

D.有时神经功能性头痛多颇剧烈

E.头痛程度与病情轻重呈平等关系