Machinery was often unprotected and accidents were frequent.是什么意思？

Machinery was often unprotected and accidents were frequent.

机器常裸露着，因此事故频仍。

machinery

n. （总称）机器，（政府等的）机关，组织，机器的运转部份，机械装置；

例句
...industrial machinery and equipment.
工业机械与设备

was

v. 用来表示某人或某物即主语本身，用来表示某人或某物属于某一群体或有某种性质（ be的过去式 ），在，存在，不受干扰；

例句
There was a terrible sadness in her eyes...
她眼神中流露出深深的悲伤。

often

adv. 常常，经常，时常，再三；

例句
Genetic abnormalities are more often associated with faults in paternal DNA than in maternal DNA.
相对于母本DNA,基因畸变往往更多地与父本DNA上的缺陷相关。

unprotected

adj. 无保护（者）的，无防卫的，不受关税保护的；v. 无保护(unprotect的过去分词)；

例句
Exposure of unprotected skin to the sun carries the risk of developing skin cancer...
皮肤没有采取任何防晒措施就在太阳下曝晒的话有得皮肤癌的危险。

and

conj. 和，与，而且，于是，然后，因此；

例句
I spend a lot on expensive jewelry and clothing...
我花很多钱购买昂贵的首饰和衣服。

accidents

n. 意外遭遇( accident的名词复数 )，事故，机遇，命运；

例句
5,000 people die every year because of accidents in the home...
每年有5,000人死于家中的意外事故。

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。

frequent

adj. 频繁的，时常发生的，常见的，（脉搏等）急促的，快的；

例句
Eleanor would later blame her mother-in-law for her husband's frequent absences.
埃莉诺过后会因丈夫经常不在家而责怪婆婆。