We don't know________ next. Let's go and ask Mr. Li.A.what to do B.to do what C.what to do it D.how to do 答案:【答案】A【解析】句意:我们不知道下一步做什么。让我们去问问李先生。考查宾语从句和动词不定式。由选项可知这里是疑问词+to do的形式,根据句意是问做什么,所以用what来提问;又因为宾语从句中what做do的宾语,故选A。 A cough is usually nothing to worry about unless it lasts for ten days . A.or more B.instead C.at most D.only