secure telephone system

例句：

1. 1. The new security system has greatly improved our safety.
   新的安全系统极大地提高了我们的安全。
2. 2. He is a man of great reliability.
   他是一个非常可靠的人。
3. 3.They secured the deal before the deadline.
   他们在截止日期之前确保了这笔交易。