octopus タコ

octopus の複数形は octopuses と octopi の二つがある。このような複数形を取る名詞は他にもいくつかあるが、一つ一つ確実におぼえることが大切だ。0:01 octopi are generally considered the most intelligent invertebrates on the planet. タコは地球で一番賢い無脊柱動物だ。

A Coconut Octopus Uses Tools to Snatch a Crab

https://www.youtube.com/watch?v=TFzpC_e44Tg  0:20 octopuses are marine animals. they live and breathe under the water. タコは海洋生物だ。
The amazing Octopus that can walk on dry land - The Hunt: Episode 6 Preview - BBC One

https://www.youtube.com/watch?v=Q36_8s5z6S8  0:55 the acquarium folks soon realize what does happen when you put these sharks and octopi in the same tank. 2:27 the acquarium staff learned something new about octopi.
Octopus Kills Shark | National Geographic

参考リンク
http://bridge-english.blogspot.jp/2017/03/alumni.html  alumni 同窓生
http://bridge-english.blogspot.jp/2013/01/three-kings.html  three kings
http://bridge-english.blogspot.jp/2016/04/20160406.html  私の英語ノート 2016/04/06