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_name_31 (date VARCHAR, opponent VARCHAR, venue VARCHAR)
### Question:
Which Date has an Opponent of manchester united, and a Venue A?
### Answer:
SELECT date FROM table_name_31 WHERE opponent = "manchester united" AND venue = "a"