Adjectives followed by an infinitive active in form but passive in meaning be + 形容词 + 不定式 在这种结构中，不定式作状语说明表语，它的逻辑宾语是句 中的主语，也称为反射不定式。 a. This apple is not fit to eat. b. This problem is difficult to solve. c. The tea is too hot to drink. d. Chinese is difficult to study. e. The two girls are very attractive to look at. f. Traffic rules are important to observe. 形容词long, short, high, low等后接主动形式的不定式表示被动意义时，它们前面必须加too，或在其后加enough。 a. The poem is short enough to learn by heart. b. The fence is too high to jump over.