Unknown phrase What does the phrase ひゅるり mean?

が and は What is the difference between は and が, and in what way would I use them?

り and し I see verb bases end with either り or し, such as with 潜入し. What is the purpose or し orり.

The word かと I see the word かと at the end of a word, such as: チェックメイトかと思われた... What does it mean?

され meaning I keep seeing the word され being used, such as 押され, and 発見され. What does it mean?

I see a verb end with れたく. What does it mean?

I see verb bases end with しor り. What do they mean?

私はちゃを見てに使用で中の文？どうしてそれわ意味ですか？

I came across the word 返さねば. What does the さねば part mean?