抗原提呈能力最强的APC是（）
A.DC
B.巨噬细胞
C.上皮细胞
D.朗格汉斯细胞
E.B细胞
参考答案：A
The little girl ______ the tail of his brother’s coat the moment she saw he would hurry away without her.
A．held on to
B．held down
C．held out on
D．held back
中 * * 党执政的组织基础是什么？
