1.concentrate的基本意思是指“吸引到或固定在一个中心之上”,既可指能被聚集、集中的事物,也可指缩聚于一点以增强其力量和强度的物质,强调人的技术、方法或努力程度，引申可指把注意力集中于…之上。
2.concentrate作“集中”“聚集”解时,可用作不及物动词,也可用作及物动词。其后接at, in等介词,表示“集中在…”，后多接表示地点的名词。
3.concentrate作“浓缩”解时,是及物动词,接名词或代词作宾语。
4.concentrate作“专心于”解时,可用作不及物动词,也可用作及物动词,其宾语多为attention, mind, energies, efforts或thoughts等词,宾语后面接介词on,表示“把…集中在…之上”。

concentrate at(v.+prep.)
〈军事〉(使)集结于某处 (cause to) gather in force at (a certain place)
▲concentrate at sth
Most of our forces have concentrated at the bridge.我们大部分兵力都已集结在大桥那里。
◇ 常用于be ～ed结构
When the enemy's ships are all concentrated at the entrance to the harbour, it must mean trouble.当敌人的船只都集结在海港入口处时,这肯定意味着要出事了。

concentrate in(v.+prep.)
集中于某处 gather at a certain place
▲concentrate in sth
The bulk of the population concentrates in the cities.大部分人口集中在城市里。
The crowds concentrated in the centre of the town near the royal palace.一群群的人聚集在皇宫附近的市中心。
▲concentrate sth in sth
◇ 用于be ～ed结构
Modern industry has been concentrated in a few urban centres.现代工业全集中在有限的几个市中心。
Industrial development is being concentrated in the South of the country.工业的发展现正集中在该国的南部。
The message is concentrated in the last paragraph.信息集中在最后一段。

concentrate on(v.+prep.)
1.专心于,把思想集中于 fix one's attention on (sth, sb or doing sth)
▲concentrate on sth/v-ing
I wish you'd concentrate on what I'm saying.但愿你能集中注意力听我讲。
You should concentrate on the road when you're driving.开汽车时注意力应集中在路上。
I can't concentrate on my work when I think of my sick child.我想到生病的孩子时就无法专心工作。
Many firms are concentrating on increasing their markets overseas.许多公司正在集中精力开拓它们的海外市场。
2.将…集中于… direct (sth such as one's thoughts) firmly on (a subject)
▲concentrate sth on sth
We must concentrate our efforts on finding ways to reduce costs.我们要集中精力找出降低成本的办法。
He concentrated his attention on the question of technology.他将注意力全都贯注在技术问题上。
If you concentrate all your energies on the study of English, you will master the language.你若全力以赴地学习英语,你会掌握这门语言的。
I tried to concentrate my attention on my English studies.我努力把我的注意力集中到我的英语研究上。

用作不及物动词
▲S+～(+A)
I can't concentrate when I'm hungry.我饿了就无法集中精力。
I can't concentrate amid all these distractions.在这些干扰中,我不能集中心思。
用作及物动词
▲S+～+n./pron.
The general decided to concentrate his forces near the capital.这位将军决定把他的部队集中在首都附近。
Concentrate the broth by boiling it.把肉汤煮得浓一些。
◇ 用于be ～ed结构
An acid solution is concentrated when it has very much acid in it.当酸溶液里含有很多酸时,它就被浓缩了。

concentrate, centre, centralize, focus
参见centre条。
concentrate, compact, consolidate, unify
参见compact条。
oncentrate, condense
这组词的共同意思是“浓缩”。其区别是:
1.concentrate指用蒸煮的方法达到浓缩溶液,而condense除了指使液体浓缩,还指使气体、水蒸气凝结成液体,且通常是因冷却而致。
2.把文章、段落、报告等进行“浓缩”得使用condense; 但要说“集中注意力”则只能使用concentrate。当说到“光线集中”时,两个词可以换用。

1.有人认为,动词concentrate本身带有“集中精神”或“思想集中”的意思,因此后面不应再有mind, thoughts等一类的词。但实际上, to concentrate one's attention〔mind, thoughts〕等用法都很普通。
2.concentrate本身就含有自身的含义,所以其后不接反身代词。例如:
我们一定要集中精力。
误:We must concentrate ourselves.
正:We must concentrate.
3.concentrate还可用作名词,意为“浓缩物,浓缩液”。例如:
This is an orange concentrate which you dilute with water.这是你用水稀释的浓缩柳橙汁。