Lesson 47: Mysterious Experiences 四个highlight均是长音i，似乎舌头没太压到位。
691. My aunt said she once saw a ghost.
692. What was that noise?
693. I think there’s something in the darkness.
694. No one knew what happened to Simon. 美音最好发成长音u，类似nu：的音，而不是类似niu的音。我没听原读，不知原读是什么。
695. The killer’s identity remained unknown.
696. The police don’t know who took the jewels.应该是长音u，你的似乎是短音u
697. Her recipe is good because of the secret ingredient.
698. His job in the war is still a secret.是不是发成类似稍微偏/啊/的音更美味？
699. She says that she can predict someone’s future.
700. Some people believe that aliens visit Earth from other planets.
701. Truthfully, there have been some unexplained occurrences around the house.
702. Mysterious noises like you heard that seem to have no natural causes.
703. Doors that seem to close on their own and objects that get moved around but not by human hands. t可以hold住，保留舌头位置。
704. A couple of months ago, a friend and I went to a psychic just for a few kicks.
705. Not everything that happens in the world can be explained.
