成人及儿童茶碱的治疗浓度低限为()
A.2μg/ml
B.5~10μg/ml
C.10~20μg/ml
D.>15μg/ml
E.>20μg/ml
参考答案:C
Jack Chan makes _____ movies.[ ]
A. comedy
B. thriller
C. documentary
D. action
剔发令