Context clues refer to the surrounding information of an unknown word in a text or a speech that helps us infer the meaning of that word. In the sentence, we can find out the meaning of the word “enthralled” by contrast: the word “but” introduces an idea that contrasts with the preceding clause “I thought I would be bored.” Therefore, “enthralled” refers to something captivating, entertaining and interesting, in other words, the opposite of something “bored.”