1 .It is a pity that Tom already left. 2 . If we now had vacation! 3 . It is a pity that you didn't visit an exhibition. 4 . It is a pity that I don't know French. 5 . It is a pity that it is raining.
Ох, мой Бог! "It's a pity" употребляют только незнающие иностранцы, либо учителя школ 60-х! В современном языке употребляется I WISH I wish I knew French, к примеру