a different kettle of fish まったくの別物

a different kettle of fish とは別の魚焼きフライパンと言う意味。イギリス英語。 3:09 lawmaking is a different kettle of fish and is often where most presidents come unstuck on their path of power. 大統領にとって立法は別物で、多くの大統領の力の及ばない領域。

How Much Power Does The US President REALLY Have?

https://www.youtube.com/watch?v=uTHVcMP0pyM  1:35 that's a whole other kettle of fish.
Debunking clichés: Is striking typically French?

参考リンク
http://bridge-english.blogspot.jp/2011/12/blog-post_05.html  まったく別の事態を英語でなんと言うか？
http://bridge-english.blogspot.jp/2013/05/blog-post_19.html  全然別物を英語でなんと言うか？

練習問題解答
a-4313 a different kettle of fish
b-4681 a whole other kettle of fish