It is a common theme in many fiction stories that the world may one day be by insects.
56. He said under his breath that he would keep the secret. The underlined part means _____.
57. The rain was coming down in buckets. This sentence means ____ .
58. The little boy has learned many Tang dynasty poems _____ though he is very young.
59. Sorry, I took your pen _____.
60. Which of the following group all belongs to the same category (范畴)? _____