The boy might be sick because he overexerted himself playing outside. Or perhaps he was around someone who was already ill and got infected. It's hard to say for sure in a cartoon!
Maybe he caught a cold or had some kind of virus. It could be that he wasn't taking good care of himself.
If you want the clearest chapter reference, go to Chapter 141. Early on, It had happened in the afternoon when Aunt Ying's son and daughter heard...; later, the chapter leans on They went straight to Jiang Li's door and insisted on thanking her..
A practical answer is Chapter 164, because it turns the idea into a concrete scene. The chapter opens with Damn, the production team is so shady, they're still doing a live..., adds pressure through Let's congratulate Jiang Yan for getting— a one-point card!" Jiang Yan: ?, and ends on The current.
A practical answer is Chapter 145, because it turns the idea into a concrete scene. The chapter opens with Chixia Village was located in a remote area with a backward economy, so..., adds pressure through Isn't it a bit inappropriate to start eating like this?, and ends on What about it?" "That's.
If you want the clearest chapter reference, go to Chapter 121. Early on, Seeing that Wen Jiaojiao's condition had improved significantly, Director...; later, the chapter leans on A doctor, donned in a white coat, hurriedly got out and immediately asked....
Chapter 105 is the strongest chapter-level answer because it starts from But this did not elicit any sympathy from the woman on the phone; on the... and follows through on However, the next second, things took a turn..
Look to Chapter 76 for the clearest answer. It begins with Thinking of this, the aunt repeatedly praised, "Girl, hearing your words..., keeps building through I'll go back and tell this to my child;
Chapter 149 is the strongest chapter-level answer because it starts from Seeing that Zhang Cheng's glass was nearly empty, Du Qinglian immediately... and follows through on Zhang, I introduced myself at the very beginning..
The best chapter pointer here is Chapter 123, "Can This Even Be Calculated?!". It opens with After He Yun also carefully rolled up her trouser legs and walked down... and closes on Seeing this, He Yun chuckled softly to himself, then glanced at his own....
Chapter 152 is the strongest chapter-level answer because it starts from While most of the villagers of Chixia Village were gathered at the village... and follows through on That shouldn't be." Zhao Lang's eye color darkened, "I'm afraid he's....
If you want the clearest chapter reference, go to Chapter 111. Early on, The main room's door was pushed open just a crack, and the head of the...; later, the chapter leans on Miss Jiang, you're still up, that's great..