Students should practice English as ______ as they can.
A:many
B:much
C:more
D:most
① ____ A. watch B. bag C. hard
② ____ A. feel B. touch C. soft
③ ____ A. smooth B. rough C. like
图1和2分别是关节结构和伸肘动作的产生,请认真看并回答: