There are some birds singing ___ the trees.[ ]

A. in

B. on

C. at

D. from

肩关节周围炎病程日久肩臂部肌肉出现萎缩，较明显的是（）

A.大圆肌

B.小圆肌

C.胸大肌

D.胸小肌

E.三角肌