X dake ja naku Y (mo) – Not only X, but y (also)
The word dake (pronounced dah - kay) means only. Ja naku is one form of the negative present copula “to be”. Ja naku is an abbreviated version of the more formal expression for “isn’t” dewa nakute, or dewai naku. Dewa has over the years become ja for all intents and purposes.
• Ringo dake ja naku banana mo kaimashita
• Not only apples but I also bought banana’s.
Works best where x and y are tangible nouns.