security optical fibre

例句：

1. 1. The security guard was very thorough in his duties.
   保安在职责上非常尽职尽责。
2. 2. The company's policy on security is to ensure the safety of its employees.
   公司关于安全的政策是确保员工的安全。
3. 3. The new security system has greatly improved our overall security.
   新的安全系统大大提高了我们的整体安全性。