皮皮学，免费搜题
登录
搜题
【单选题】
人的屈肘运动是由肱二头肌和肱三头肌等骨骼肌在神经系统的调节下，协作完成的．如图所示①为肱二头肌、②为肱三头肌．当屈肘时，①和②所处的状态是（ ）A.
①和②同时收缩
B.
①和②同时舒张
C.
①收缩、②舒张
D.
①舒张、②收缩
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】Do you approve of the idea that success can be measured ________ money alone? [ ]
A.
in case of
B.
in terms of
C.
in the opinion of
D.
in favour of
【单选题】Swimming alone ___be ____erous. Do be careful.
A.
need; highly
B.
may; high
C.
can; highly
D.
can; high
【简答题】Yang alone can do the work, and there are twenty students in the class.