(1)He started work in our company 10 years ago.(work 是名词)

(2)He started to work in our company 10 years ago.(work是动词)

(3)He started working in our company 10 years ago.(work是动词)

备注：单词，work可以当作名词，也可以当作动词。

【1】work当作名词使用，可以作“介词或者动词宾语成分”，可以放在动词前作主语，可以放在系动词后作表语

They are in work .他们有工作。

He started work as a security guard.他开始工作时做保安员。

It is difficult to find work in the present economic climate.

在目前这种经济大气候下很难找到工作。

I'm still looking for work.我仍在找工作。

She's planning to return to work once the children start school.她正计划孩子一入学就恢复上班。

There is plenty of work to be done in the garden.花园里有很多活要干。

Taking care of a baby is hard work .照看婴儿是件苦差。

【2】work当作动词使用，可以作“谓语动词或者非谓语动词”

I can't work if I'm cold.我要是觉得冷就干不了活。

I've been working at my assignment all day.我整天都在做作业。

He is working on a new novel.他正在写一部新小说。

She's outside, working on the car.她在外面修理汽车。