without the ability to think carefully, they cannot fully participate in our democracy.在這個句子中without the ability to think carefully作整個句子的狀語。
第二類是非謂語動詞作狀語,其中包括不定式作狀語,不定式作狀語時一般表目的,比如I went to bed early to get enough sleep. 句子中的 to get enough sleep便是不定式作狀語表目的。
第三類是獨立主格,一般形式是with(可以省略)加上名詞/代詞的主格,再加上不定式、現在分詞、過去分詞、形容詞短語、介詞短語。例如
(With) all flights canceled because of snowstorm, we decided to take the train. 在這句話中(With) all flights canceled because of snowstorm是獨立主格,因為它的邏輯主語和主句不一致,前面cancelled的邏輯主語是flight,而主句的主語是we。