Pattern Practice: A 是 B, A 不是 B

The pattern

Remember the rule: 是 is an equals sign between two nouns that never changes shape, and 不 slots in right before it for the negative.

A 是 B: 我是学生. A 不是 B: 我不是学生. That's all there is -- 是 never changes for the person (no am/is/are) and never changes for time.