Here are the recommended types of books for each reader:

1. "I like stories about dark nights, empty houses, and strange noises!"

   • Recommended book type: Horror story

2. "I want to read about people falling in love."

   • Recommended book type: Romance novel

3. "I like reading about criminals and their motives."

   • Recommended book type: Mystery or Crime thriller

4. "I love stories about extraterrestrials and alien universes."

   • Recommended book type: Science fiction

5. "I want to read about monsters!"

   • Recommended book type: Fantasy or Horror

6. "I like reading about secret agents."

   • Recommended book type: Spy thriller or Espionage fiction

For the grammar exercise, please provide the content of the postcard that needs completion, and I'll help you with using the present perfect form of the verbs.