Shouldn't field be "die Flur"? Ich stand allein auf weiter Flur <-> Ich stand allein auf weitem Flur? Or is both allowed?
I'm sometimes confused, too. Accoding to the Duden Joghurt can be der, die and das.
Tunnel is another funny word. You can say "der Túnnel", or "das Tunnél", both meaning tunnel, but notice the difference in the pronounciation.
