押さえ

In a sentence

• 重要なポイントを押さえながら勉強しましょう。

  Let's study while focusing on the important points.

  Here, 押さえながら means 'while focusing on' or 'holding down in relevance to an abstract concept'.

• このボタンを押さえて、機械を動かしてください。

  Hold down this button to operate the machine.

  Here, 押さえて means 'press firmly' or 'hold down' in relation to a physical object.

• 帽子が飛ばないように、手で押さえた。

  I held my hat with my hand so it wouldn't fly away.

  Here, 押さえ means 'to hold firmly or keep down physically'.