As East, you are dealt:
You (East) see the auction shown below (2NT was invitational).
Partner leads the 6 (standard) and dummy plays low.
What do you play?
Declarer plays the 4 as shown. What next?
On your heart return, declarer plays the ace and partner plays the jack. What is going on?
Partner also has the queen.
Partner has lost his mind.
Declarer has the queen.
Other -- can't tell who has the queen.
Declarer next plays a low diamond and you win your 10 as shown below. Then what?
Declarer (as expected) wins the Q, partner playing the 5. If you recall, partner led the 6 (4th-best), so you know he started with 5 hearts. He now sits with 2 good hearts. Declarer now crosses to the A and leads the Q as shown. And you?