Will you check the following English sentences?

Question

1. Paying attention to the intonation mark, listen carefully. (Do I have to use 'mark'?)

2. Put your tongue between your upper teeth and lower teeth, and say th by letting the air over your tongue abruptly.

3. If the question has a rising intonation, mark an upward arrow, if it has a falling intonation, mark a downward arrow in the parentheses.

4, Blow out the candles on the birthday cake. He is trying to blow out the candles on the cake. (candles or candlelights?)

5. Do you have any brothers or sisters?
No, I don't. I am an only child./ I am the only child./ I am an only son. / I am an only daughter. (Which expressions are right?)

-------------------------...
I have posted sentences. Would you check whether they are grammatical or not. I'd like to use correct English expressions.

Answer 1

#1 No, you do not need mark there.
#2 The "th" is an elongated sound, so you do not need the word abruptly. Use the word "blowing" instead of "letting".
#3, Put a semicolon after arrow.
#4. Candles is correct.
#5. The first two of those would be correct ways to answer that question.