handbasin

He washed his hands on the handbasin.→He washed his hands in the handbasin.

介词选用错误：handbasin 是容器，洗手动作发生在内部，应使用 in 而非 on。汉语中常受“在…上”表达的影响而误用 on。

I need handbasin for the bathroom.→I need a handbasin for the bathroom.

冠词缺失：handbasin 是可数名词单数，前面需要不定冠词 a。汉语没有冠词，学习者容易遗漏。