By the 1960s, many shipyards were struggling.是什么意思？

By the 1960s, many shipyards were struggling.

到20世纪60年代，许多造船厂都在勉强支撑。

by

prep. 在…旁边，表示方式，由于，经过；adv. 经过，表示保留或保存时用，短暂拜访；

例句
...expensive make-up that we saw being advertised by a beautiful model...
我们所见的由一位漂亮模特代言的昂贵化妆品

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

many

adj. 许多，多的；pron. （与复数动词连用）大多数人；

例句
There are many people who still find the act of abortion abhorrent.
仍有很多人对堕胎行为表示厌恶。

Shipyards

n. 船坞( shipyard的名词复数 )；

例句
In 1980, strikes at the Lenin Shipyards gave birth to the Solidarity trade union.
1980年，列宁造船厂的罢工致使团结工会得以成立。

were

be的过去时复数和第二人称单数形式，有时代替 was,用于条件从句、动词 wish 之后等；

例句
Shops, houses, and vehicles were set ablaze.
店铺、房子和车辆全都陷于火海。

struggling

adj. 奋斗的，努力的，苦斗的；v. 搏斗( struggle的现在分词 )，奋斗，努力，争取；

例句
Tired old trucks were struggling up the road below us, belching black smoke...
破旧的卡车冒着黑烟艰难地沿着我们下方的公路往上爬。