We can learn about using (use) the telephone , asking _(ask) and answering(answer) questions.
第一空因为有介词about,所以填using,之后为了并列,故都填ing形式
有不会的可以再问我asking _(ask) and answering(answer) questions在句中作什么成分？using the telephone asking answering questions都是作为learnabout的宾语的My brother was lying in bed, watching TV.这句话中， watching TV作什么成分？谢谢。现在分词表示伴随是状语