seem appear prove等词后面为什么加不定式?

seem appear prove等词后面为什么加不定式? 系动词＋名词 举例系动词look，feel，sound，smell，taste，seem，appear，go，prove，turn等＋名词。 seem,look,appear的区别 appear to=seem吗? appear 和seem的区别 appear,seem,look有什么区别? APPEAR 和 SEEM 有什么区别 look,seem 与appear 的区别 chance/happen/seem/appear/pretend to do look,seem,appear有什么区别? 英语中类似appear to,seem to,tend to这些词是什么词性?后面为什么跟be或动词原型? feel like seem to 和 appear to 什么区别? remain to be seen为什么等于appear/seem to be 有这个句型么?S+(seem/appear)+to+(v/adj.) appear和seem为“似乎”之意时有何区别? seem和appear的用法是不是几乎一样 英语系动词的问题感官系动词很多如seem appear 等他们后面一般接动词不定式如：he appeared to be very young这里的be是be动词的原型be动词也是系统词那么1个句子有2个系动词应该怎么理解? 系动词seem,appear什么时候接不定式怎么判断什么时候接不定式什么时候不接