confidential phone

例句：

1. 1. The company's confidential information is classified as top secret.
   公司的机密信息被分类为最高机密。
2. 2.He kept the confidential details of the project a secret until the end.
   他保守了项目的机密细节，直到最后才透露。
3. 3.The government has made it clear that all confidential documents must be kept secure.
   政府已经明确表示所有机密文件都必须得到妥善保管。