Question

麻烦分析一下这两句话的句子成份，尤其是that,谢谢

To the readers, the whale can be viewed as a symbol of the physical limits that life imposes upon man.
Here the sea symbolizes nature that remains moving but unmoved .

Answer 1

To the readers(补语), the whale（主语） can（谓语） be viewed as a symbol of the physical limits that （引导同位语从句，做the limits的同位语。因为从句主谓宾完整。）life imposes upon man.
Here the sea（主语） symbolizes（谓语） nature（宾语） that （引导宾语从句，修饰nature, 在宾语从句里面做主语。因为从句缺主语。）remains moving but unmoved .