是不定代词。不定代词是英语语法术语,在句中可以作主语、宾语、表语、定语和状语。不定代词是不指明代替任何特定名词或形容词的代词。someone,作代词时意为“有人,某人;重要人物”。
Someone explain that one to me!
有人解释说,一到了我!
Someone must be at the back of this.
这事一定有人在背后捣鬼。
He found someone on him.
他发现有人在跟踪他。
some(something,somebody,someone),any(anything,anybody,anyone),no(nothing,nobody,noone),every(everything,everybody,everyone),all,each,both,much,many,(a)little,(a)few,other(s),another,none,one,either,neither等。