In middle age的用法和样例：
- He admires the chivalry of knights in Middle Ages.
- Last fall, firmly in middle age, I learned that I needed braces.
- Apoplexia most occur in middle aged people.
- It begins in middle age and proceeds to death in several years.
- The stresses of business had beaten John to his knees in middle age.
- The findings suggest that a heavier weight in middle age may mean a higher risk of dementia later in life.