担保法规定，定金合同自（）时生效。
A.签订定金合同
B.实际交付定金
C.主合同签定
D.主合同履行
参考答案：B
They were_____ popular that their fans formed clubs in order to get more familiar_____ them.
A．so, with
B．too, with
C．so, to
D．too, to
试说明原毛中含有哪些杂质及这些杂质的主要化学成分？
