There is a question in the Kanzen Master N2 Textbook:

> この薬は、_____上でお飲みください
>
> a. 食事が終わった
>
> b. 医師が説明した
>
> c. 説明書をよく読んだ

According to the answer sheet, the answer is c.

But I don't understand why a. and b. are wrong.

From what I understand of 上で in this context

```

    A上でB
    
    まずAします。それからB・準備としてまず～してから、その後で次に続く行動をする
    
    Where it is necessary to do A first before doing B, A has significance
    for what happens to B
    
```

When asking someone else, a sentence was given to me that is natural

お話は食事をした **上で** お聞きします

If this sentence is correct, why is a. wrong, what is the difference?
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2019-11-08T11:34:17.590
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2019-11-08T11:34:17.590
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question
grammar nuances sentence
Usage of 上で in this sentence