Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_18042031_16 (against VARCHAR, date VARCHAR)
### Question:
What country did Gil play against on 21–23 september 2007?
### Answer:
SELECT against FROM table_18042031_16 WHERE date = "21–23 September 2007"