Here are the answers based on the provided questions:

**Pronunciation:**
11. **C vehicle** - The underlined "v" in "vehicle" is pronounced differently than the "h" in "history," the "h" in "healthy," the "h" in "hundred," and the "h" in "excuses."

12. **A subjects** - The underlined "j" in "subjects" is pronounced differently than the "s" in "classrooms," "c" in "classes," and the "x" in "excuses."

13. **B changes** - The "ch" in "changes" is pronounced differently from the "c" in "excuses," "q" in "quizzes," and the "s" in "lessons."

**Stress Pattern:**
14. **C science** - The stress pattern in "science" is different from the other words (problem, playground, advice).

15. **A presentation** - The stress pattern in "presentation" is different from the other words (activity, obligation, independence).

**Use of English:**
16. **D suffer** - The correct option is "suffer": "Unfortunately, many students suffer from bullying at school nowadays."