涩圈
参考答案：瓷坯在叠烧时，将下面的器物内底刮掉一圈釉药，这样，器底中心有釉，而相叠处无釉；烧成后，无釉处即成“涩圈”。
Lauren Berger started out as a clueless college freshman at the University of Central Florida，________ only work experience was serving at a seafood restaurant.
A．which
B．when
C．whose
D．where
水情自动测报系统通信主要采用（）传播。
A、地波
B、电离层
C、直射
D、地下
