Petrologen
油母岩质
🗣️ 情景例句
She went to a school-board meeting.
她去参加联合校董会的会议。
What do you know about the tenth century?
有关十世纪的事你知道些什么？
namely 6 million million miles.) Radio waves also travel at the speed of light,
即6万亿英里）。无线电波也是以光速传播的。