1) What 5 things should you never do?? (5 points)

1, Saying "I don't know"

2, I'll try.

3, OK / Oh yes

4, Things are really busy today. So it's taking a bit longer than usual.

5, What?

2) What phrases can you use instead? (5 points)

1, "I'm not sure, but I can find out." or "I'll find out for you." or "Let me come back to you on that"

2, "I can do it" or "I don't think I can manage it by 2, but I can definitely?have it done by 4. Would that be OK?"

3, "I'm sorry. I understand. Let's see what we can do ?"

4, "I'll be with you in a moment","sorry to keep you waiting. I'' be right there. "

5, "I'm sorry. I missed that" "would mind just repeating that for me. I missed it?"

3) How helpful was this advice?? Explain your answer. (3 points)

It's quite helpful.
Actually, I often make such mistakes in my daily life. This video is very useful can make me sound more professional.