a head office的用法和样例：
- Our head office can put you in touch with a branch in your area.
- Now we work in over 20 provinces and municipalities China-wide with a Head Office in Beijing and regional offices in Kunming, Hefei, Urumqi, Lhasa and Shanghai.
- A serpent having a head at each end of its body.
- Have you got a reply from your head office?
- Tom is taller than John by a head.
- The head office is in the central part of the city.