現(xiàn)在進(jìn)行時由助動詞be的現(xiàn)在時加上動詞的現(xiàn)在分詞構(gòu)成,它的基本用法是表示現(xiàn)在正在進(jìn)行的動作,所配的時間狀語是now、at present、at this moment、these days等.如：
What are you doing now,John?
Where are you going?
Our team is leading.
The telephone is ringing.
George is translating a book now.（動作在包括現(xiàn)在在內(nèi)的一段時間當(dāng)中進(jìn)行）
I'm not doing anything at present.
We are trying to plan our future.
We are eating more meat now.
He is speaking English much more fluently than he used to.
你給出的句子,題干中看到現(xiàn)在分詞,現(xiàn)在分詞前面當(dāng)然配助動詞be,構(gòu)成現(xiàn)在進(jìn)行時,排除A和D,Mary和Kate是兩個人,是復(fù)數(shù),選擇C,表示“瑪麗和凱特在那里吃什么?”希望我能幫助你解疑釋惑.