Possible Clues:

• Commonly
• Time and again, to Yeats
• Often, poetically
• Frequently (archaic)
• Frequently, to Browning and others
• With regularity, to Whitman
• Time and again, to Whitman
• Frequently found in poetry?
• ''__ I had heard of Lucy Gray . . .'': Wordsworth
• Time and again, in verse