### Chinese: 美国海军舰队中14艘“雷鸣潜艇”的行踪通常是被严格保密的。
### English: The whereabouts of the 14 "Thunder submarines" in the U.S. Navy's fleet are usually closely guarded.
### Errors: There is a minor error at ""Thunder submarines"". There is a minor error at "'". There is a minor error at "guard".

### Improved English: The whereabouts of the 14 “Boomer Submarines” in the US Navy fleet are usually strictly confidential.