相标志
参考答案：
指最能反映沉积相特征的岩性的、古生物的和地球化学的标志，它是相分析及岩相古地理研究的基础。
The phone was ringing. However, Maria continued reading in her study nothing had happened. [ ]
A. as though
B. since
C. now that
D. even if
标准结构
