Agnatha
n. 无颚类脊椎动物
🗣️ 情景例句
My stomach growls at me when I'm hungry.
我的肚子在咕噜咕噜地向我发牢骚呢！
How long will it take to have this radio fixed?
修理这收音机要多久？
Alternatively, if the star were small, the life-supporting planet would have to have a close orbit round it and also provide the perfect conditions for life forms to develop.
反之，如果恒星很小，维持生命的行星就要在离恒星很近的轨道上运行，而且要有极好的条件才能使生命得以发展，