— I'm sorry I can't go with you. I have a lot of homework to do.
A:Come on
B:Take care
C:See you
D:Thank you
近年,基里巴斯、库克群岛、瑙鲁、西萨摩亚和图瓦卢等低地岛国面临着被淹没的威胁。回答下列小题。
读黄河流域局部图,回答问题.
利用重力与浮力的关系解释物体在水中沉浮的原因。