doing my homework是整个句子的谓语部分,主语是I,过去进行时was+doing ,doing 实意动词“做...”my homework是动词do的宾语。 介词短语at home 是地点状语(放句中,一般地点和时间状语可以放句后,这是最标准的位置,也可以放句首,以突出状语部分,状语放在句中,也表示强调状语,这里是强调是在家里做作业) 介词短语at that time是时间状语(放句后)
整个完整的句子,较标准的即:I was doing my homework at home at that time.追问