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_22 (launched VARCHAR, commissioned VARCHAR, bow_number VARCHAR)
### Question:
When did the ship that was commissioned July 1948 with a bow number of ps-31 launch?
### Answer:
SELECT launched FROM table_name_22 WHERE commissioned = "july 1948" AND bow_number = "ps-31"