これ
これ means “this” and refers to the item being checked in 「これは大丈夫ですか。」. It is used before は to make the item the topic, as in the new example 「これは私の本です。」.
は
は marks これ as the topic in 「これは大丈夫ですか。」, giving the sense “as for this.” It follows the topic and comes before the information or question about it.
大丈夫
大丈夫 means “okay” or “all right” in 「これは大丈夫ですか。」. Here it asks whether the item or situation is acceptable; the same expression can be used when checking if someone is okay.
です
です politely presents the description 大丈夫 in 「大丈夫ですか」. With か, it helps form a polite question, and it is commonly used after a noun or descriptive expression.
か
か marks 「これは大丈夫ですか。」 as a question. It is placed at the end of a polite question and can also be used after other polite questions such as the new example 「忙しいですか。」.
あなた
あなた refers to the person being addressed in 「あなたのバッグ」. With の, the phrase means “your bag”; this form is used when identifying whether something belongs to the listener.
の
の links あなた and バッグ in 「あなたのバッグ」 and shows that the bag belongs to or is associated with the person. The reusable pattern is 「AのB」, meaning “B related to or belonging to A.”
バッグ
バッグ means “bag” in 「あなたのバッグ」. It names the item whose ownership is being checked, and it can be used after a possessive phrase such as 「私のバッグ」 in a new example.
ここ
ここ means “here” in 「ここに誰か座っていますか。」 and points to the place near the speakers. It is followed by に when identifying the place where someone is sitting or something exists.
に
に marks ここ as the location in 「ここに誰か座っていますか。」. In this sentence, it identifies where the person may be sitting; the pattern is 「場所に人がいます」 for saying that someone is at a place.
誰か
誰か means “someone” in the question 「ここに誰か座っていますか。」, asking whether any person is there. It is used before the action or state being checked, as in the new example 「誰か来ました。」.
座って
座って is the form used in 「座っています」 to express sitting as an ongoing state. It connects with います in this dialogue, and the reusable pattern is 「座っている」 or its polite form 「座っています」.
います
います completes 「座っています」 and politely expresses that a person is in the state of sitting. It is used with a person or other animate subject, as in the new example 「ここに人がいます。」.
今
今 means “now” in both 「今、忙しいですか。」 and 「今、準備できていますか。」. It sets the time being asked about and commonly appears at the beginning of a sentence.
忙しい
忙しい means “busy” in 「忙しいですか。」 and asks about the listener’s current availability. It can be used with 今 to ask about someone’s present situation, as in 「今、忙しいですか。」.
準備
準備 means “preparation” in 「準備できていますか。」. Together with できています, it refers to being ready or having the preparation completed; the reusable pattern is 「準備ができています」.
できて
できて connects 準備 with います in 「準備できていますか。」 and contributes the idea that the preparation has been completed or is ready. The full reusable expression is 「準備ができています」, meaning “be ready.”
手伝い
手伝い means “help” or “assistance” in 「手伝いが必要ですか。」. It is the thing whose necessity is being checked, and it can be used when offering or asking about assistance.
が
が marks 手伝い as the thing that is needed in 「手伝いが必要ですか。」. The pattern 「Nが必要です」 means that N is needed, so the question asks whether help is necessary.
必要
必要 means “needed” or “necessary” in 「手伝いが必要ですか。」. With 手伝いが, it asks whether help is required; the reusable pattern is 「Nが必要です」.