1994年我国汇率并轨,当时重新确定人民币对美元汇价的基础是()
A.黑市汇率
B.官方外汇市场汇率
C.外汇调剂市场汇率
D.银行间外汇市场汇率
参考答案:C
I had just started back for the house to change my clothes _____I heard my name called. [ ]
A. as
B. for
C. while
D. when
简述何谓黏膜白斑。