An uncertain and nervous witness was being cross-examined. 

The lawyer thundered at him, "Have you ever been married?"

"Yes, sir," said the witness in a low voice.  "Once."

"Whom did you marry?"

"Well, a woman."

The lawyer said angrily, "Of course you married a woman.  Did you ever hear of anyone marrying a man?"

The witness said meekly, "My sister did!"