Gainsborough is known as an unemployment blackspot.是什么意思？

Gainsborough is known as an unemployment blackspot.

众所周知，盖恩斯伯勒失业严重。

Gainsborough

[人名] [英格兰人姓氏] 盖恩斯伯勒住所名称，来源于古英语，含义是“反对+堡垒，城镇”(against+fortress,town)，[地名] [加拿大、英国] 盖恩斯伯勒；

例句
The Gainsborough Hotel was really a boarding - house, a place people lived in for long stretches.
盖恩斯巴勒旅馆是个真正的供应膳食的寄宿处,人们长期住在那里聊度时光.

is

vt.& vi. 是（be的三单形式；n. 存在；

例句
Bollinger 'RD' is a rare, highly prized wine.
博林格RD香槟是一种名贵的备受推崇的葡萄酒。

known

adj. 大家知道的，已知的，知名的，向某人作自我介绍；v. 知道( know的过去分词 )，看到过，听到过，经历过；

例句
I've known clients of mine go to absurd lengths, just to avoid paying me a few pounds...
我知道我的一些客户就为了少付我几英镑，可谓无所不用其极。

as

adv. 同样地，一样地，例如；prep. 作为，以…的身份，如

例句
As far as I can recall, Patti was a Smith.
我记得帕蒂是姓史密斯的。

an

art. 一（在元音字母前代替不定代词a），一任一某一，一个；

例句
He started eating an apple...
他开始吃苹果。

unemployment

n. 失业，失业率，失业状况，失业人数；

例句
He will appeal to the state for an extension of unemployment benefits...
他将呼吁国家延长领取失业救济金的时限。

blackspot

黑点（镀锡板缺陷），黑斑，盲点，斑痕；