题目

当我们伸肘时，肱二头肌和肱三头肌的舒缩情况分别是（ ） A.舒张，舒张 B.  舒张，收缩  C.收缩，收缩    D.收缩，舒张 答案：BShe is busy. She has much homework to do.A.manyB.a lot ofC.a littleD.a few