Passage 1: "The girl's eyes twinkled like stars in the night sky."
Explanation: This passage contains a metaphor comparing the girl's eyes to stars. It doesn't use the words "like" or "as" to make the comparison, but rather uses the word "twinkled" to draw a parallel between the sparkle in the girl's eyes and the twinkling of stars.
Passage 2: "The waves crashed against the shore like thunder."
Explanation: This passage also contains a metaphor, comparing the sound of the waves crashing to the sound of thunder. It uses the word "like" to make the comparison, but could just as easily have omitted the word "like" to create the metaphor: "The waves crashed against the shore with a thunderous roar."
Therefore, both passages contain examples of metaphors.