I could never fill her shoes.

promotional: 홍보용의 (promotional video,campaign) 

demote: 강등시키다. [relegate]

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Congrats, I heard you were promoted today and taking over Amy'job.

The waves don't seem so high.

[파도가 높아보이지 않네요.]

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This promotion is good money, but I could never fill her shoes. 

[승진하면 돈은 많이 벌지 하지만 Amy만큼 못 할 것 같아.]

---------------------------------------------It's a heavy workload, but you'll adjust in no time.

[업무량이 많긴 하지만 곧 적응 할 거야.]

He will be back in no time.

You will speak fluent English in no time.

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There was a time at one of my previous jobs where I received promotion.

(한 번 ~ 해 본 적이 있다.)

There was a time when I would swim every day.

take over = 일을 인수하다. 직책을 받다

I am taking over from here. [= I am in charge]

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I couldn't help but wonder "How am I going to do my job as well as the person before me?"

= 내가 전임자만큼 잘할 수 있을지 생각을 안 할 수가 없없다.

I am sorry, I can't help but laugh.

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