Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What are the categories of events that occurred after 2007 that were World Championships?

### Inputs:
table_name: table, columns: ['Competition', 'Venue', 'Year', 'Category', 'Result']

### Response:
SELECT Category FROM table WHERE Year > 2007 AND Competition = world championships