The second attack was so serious that his airway swelled, preventing him from breathing, his blood pressure dropped suddenly, and his heart stopped for a moment.

第二次发作很严重，他的气道肿胀，无法呼吸，血压突然下降，心脏停了一会儿。

However, this is not so serious.

然而，这不是那么严重的。

Client: Yes, but not so serious.

顾客：是的，不过不严重。

Why are you so serious?

你为什么如此严肃？

But do not so serious, I am not agree with it.

但是不要太认真，我不这样认为。