Hi Cathy, If there were NO sunlight, we could not live. (This one is correct) We are using a quantifier to describe the quantity of sunlight we receive. In this case, we use the quantifier "no", which means not present. We use "not" together with modal verbs (such as "should", "would" etc) to form a negative sentence. (Example: There would not be sunlight.) Therefore, the correct sentence should be: "If there were NO sunlight, we could not live." Hope this helps. Cheers, Lance