英语语法问题2请写出判断依据,tosurfat,surfing,
请写出判断依据 ,to surf at,surfing ,surfing at,surf
答案是 做形式主语，这是个典型的主语从句。 surfing on the internet是真正主语。全句正常顺序surfing on the internet is a terrible waste of time and energy for teenagers.