Could black have taken the queen here? Could black have taken the queen here?

Note the bishop and the knight 

 [FEN "r5k1/1b3Qpp/5b2/p1p1N3/2P2P1P/8/P1N5/K4Rn1 w - - 0 1"]
 [Title "Can black take the queen?"]
No, black could not have taken the queen. Taking the queen would put black's king into check, which is not legal. Black cannot take the knight either because black's king would still be in check.