小石子从墙上掉下来，扑通一声落入水中。

The small stones fell from the wall, ___plopping into the water below.

他回家后直接重重地坐在了沙发上。

After getting home, he ___plopped down heavily on the sofa.

她随手把钥匙扔在桌上。

She ___plopped the keys onto the table carelessly.