有there is nothing to do but do这样的固定句型吗？是什么意思？

j固定句型是: There is nothing to do but doing 除了做...无事可做 but在这里是个介词,后面+动名词, 句中的to do作为定语修饰nothing There is nothing to do but finishing my homework. 除了做作业,我没事干.