考研英语语法填空真题:后接非谓语动词后接不定式的被动式时,有时可以省略to be,而只保留过去分词(尤其是当其中的过去分词可用作形容词时更是如此)。
如:Ann and Robert seem (to be) made for each other. 安和罗伯特真似天生的一对。She didn’t seem (to be) convinced by the argument. 这个论点似乎没有使她信服。
但后接不定式的进行式时,通常不能省略to be,因为seem后习惯上不接现在分词作表语。所以,下面各句中的to be均不宜省略:History seems to be repeating itself. 历史似乎在重演。He seems to be saying something. 他似乎在说什么。His health seems to be improving little by little. 他健康状况看来正在好转。
注:如果seem to be doing sth结构中的doing 不是现在分词,而是形容词,则可省略其中的to be。如:His idea seems (to be) exciting. 他的主意看来令人激动。She seemed (to be) lacking in enthusiasm. 她似乎缺乏热情。