a card of buttons的用法和样例：
- To play a card of the same suit as the one led.
- To punch identical hole patterns into each punch card of a card deck.
- A card game in which the players lay wagers on the top card of the dealer's pack.
- A trump can take a trick even when a card of a different suit is led.
- It's hard to make a card with 3 or 2 of heart.