a bicycle chain的用法和样例：
- You didn't have to see Varmus pedaling through traffic;all you needed for the mental picture was the up-close sound of traffic and a bicycle chain gliding through a derailleur.
- He is learning to ride a bicycle.
- The chain is an important part of a bicycle.
- It's uphill work learning to ride a bicycle.
- This hill is too steep to ride up on a bicycle.
- She is too little to ride a bicycle.