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

### Instruction:
What is the airing date for a modern drama with more than 21 episodes?

### Inputs:
table_name: table, columns: ['Airing date', 'English title (Chinese title)', 'Number of episodes', 'Genre', 'Official website']

### Response:
SELECT Airing date FROM table WHERE Genre = modern drama AND Number of episodes > 21