surface指物体的“面”“表面”时,是可数名词,可加不定冠词,也可与数词连用。surface指“水面”“液体的表面”时,常用单数形式。surface用于比喻,可指人或事物的“表象”“外表”“外观”,也常用单数形式。

on the surface
在表面上,在外表上 when not observed, thought about, etc. deeply or thoroughly; superficially
The scheme seems on the surface to be quite practical.这方案表面上看来似乎很实际。
On the surface, she's a charming, helpful person.从表面上看,她又动人,又肯助人。

scratch the surface
对待或处理问题不深入彻底 treat a subject or deal with a problem without being thorough
This essay is so short that it can only scratch the surface of the topic.这篇文章很短,只能对这一问题作肤浅的探讨。
The famine is so bad, aid can only scratch the surface.饥荒十分严重,援助也只是杯水车薪。

A cube has six surfaces.立方体有6个面。
The wooden surface had a beautiful shine.这木头表面有美丽的亮光。
Steam is condensed into water when it touches a cold surface.蒸气接触冷的表面时,即凝结为水。
The outer surface of a ship's hull is very hard.船壳的外表面非常坚硬。
The sea covers almost three-fourths of the earth's surface.海洋几乎占地球表面的四分之三。
The surface of the water was not tranquil during the storm.在暴风雨中水面不再平静。
He struggled to the surface as the water dragged him down.水流使他下沉,可他挣扎着浮出水面。
Tiny rippling whirlpools on the water's surface suggest that the ponds are full of fish.水面的小漩涡说明池塘里都是鱼。
A strong wind swept the surface of the sea.大风掠过海面。
He did not merely see the surface but penetrated beneath.他不仅看到事物的表面,而且透过它看到本质。
Beneath her self-confident surface, she's quite unsure of herself.她看上去信心十足,实际上缺乏自信。
You must not look only at the surface of things.看事物不能只看表面现象。

他仅仅表面上聪明。
［误］  His cleverness is only on surface.
［正］  His cleverness is only on the surface.
［析］  on the surface用作表语,作“表面上”或“外表上”解,是习惯用法,其中定冠词the不能省略。

surface还可用作动词,表示“在某物上面加表层”“浮到水面”“重新出现”“睡醒,恢复知觉”。例如:
After living abroad for years, she suddenly surfaced again in London.她在国外居住多年后,突然在伦敦重新露面了。
Their old rivalry soon surfaced when they met again.他们重逢时,昔时之明争暗斗旋即死灰复燃。
He finally surfaced at midday.他终于在中午醒过来了。

［同义词］   cover, covering, exterior, outside