be動詞を使った where / what / who の疑問文では、まず疑問詞を置き、そのあとに be動詞を続けます。それぞれの疑問詞は聞く内容が決まっています：where は場所、what は物や事柄、who は人をたずねます。
疑問詞から始める
Amina is at home. → Where is Amina?
This is a cat. → What is this?
She is happy. → Who is happy?
Not "Where Amina is? (this is the statement order)" — say "Where is Amina? (question word first, then is)". 疑問詞を文頭に置き、そのあと名前の前に is を移動させます。
やってみよう: Amina is at the library. Aminaがどこにいるかたずねてみましょう。 答え: Where is Amina? — 疑問文では Amina の前に is が来ます：Where is Amina?。「Where Amina is」は肯定文の語順です。
Where is Amina? — She is at home.
What is this? — It is a cat.
Who is happy? — Amina is happy.
Where — asks about a place
What — asks about a thing
Who — asks about a person
How are you?
How は、人の調子や様子をたずねることばです。答えは fine や good のようなことばで、場所やものではありません。
How are you? I am fine, thank you.
How is Lars today? He is tired.
How are you this morning? I am good.
Not "Where are you? (this asks about a place)" — say "How are you? (this asks about you today)". How は、人の調子や様子をたずねます。
やってみよう: ___ is Lars today? - He is fine. (How / Who / Where) 答え: How — 「He is fine」は Lars の様子を言っているので、疑問詞は How です。Who は人を、Where は場所をたずねます。
be動詞で答える
答えにも is、are、am のどれかが必要です。だれについて、何について答えるかに合わせて選びます：It is… / They are… / I am…
Where is Sofia? She is at work.
Where are the keys? They are in my bag.
Where are you? I am at home.
Not "Where is Sofia? She at work." — say "Where is Sofia? She is at work.". 答えにも is、are、am が必要です。
やってみよう: Lars: Where are your keys? Sofia: They ___ in my bag. Sofia の答えを完成させることばを選んでください。 (is / are / am) 答え: are — They は2つ以上を表すので、答えには are を使って They are in my bag. と言います。is は1人の人か1つのもの、am は I のときだけです。