Read the sentence from the passage. You remembered so keenly the special and singular length of some such space as your elders called a half-an-hour—so keenly that you spoke of it to your sister, not exactly with emotion, but still as a dreadful fact of life.

Based on the context of the passage, the word special suggests that a half hour is something that is . The phrase from the passage that best helps the reader understand the meaning of special is .