父母应该对青少年严格，以设定清晰的界限。

Parents should be ___firm with their teenagers to set clear boundaries.

作为主管，他对新实习生相当严格。

As a supervisor, he was quite ___firm with the new interns.

领导很严格，确保每个人都遵守规则。

The leader was ___firm in making sure everyone adhered to the rules.