---Could you tell me how to improve spoken English?

---Well, just take every chance to practise ______and don't be shy.  

A． speak

B．to speak

C． speaking

D．spoke

缴费单位的（）等社会保险登记事项发生变更时，应当依法向原社会保险登记机构申请办理变更社会保险登记。

A.单位名称

B.住所或地址

C.主管部门

D.开户银行账号