certificate for rural doctors

例句：

1. 1. This certificate is valid for three years from the date of issue.
   这张证书从签发之日起三年有效。
2. 2. The rural doctors are required to undergo regular training and certification.
   农村医生需要接受定期培训和认证。
3. 3. The certificate will be issued upon successful completion of the training program.
   证书将在完成培训程序后发放。