Correct

扑通

/ pūtōng /
Strokes

Definition

(onom.) sound of object falling into water/plop

Example

As an Onomatope

flop; thump; splash; pit-a-pat

1
de
xīn
tōng
扑通
tōng
扑通
de
tiào
  

Her heart went pit-a-pat.

2
tōng
扑通
shēng
diào
jìn
shuǐ
  

He fell into the water with a splash.

3
tōng
扑通
shēng
一声
guìxia
跪下

flop down on one's knees

4
tōng
扑通
shēng
diēdǎo
跌倒

fall with a flop