谁能帮我分析一下这个英语长句的句子结构

While（引导状语从句） company managers have known about the benefits for a long time, many （主语）have done （谓语）little 宾语about it（双宾语）, （之后为 it 的同位语从句） [sceptical of （之后是宾语从句，即 of ... 介宾短语）whether they could trust their employees to work to full capacity without supervision, or concerned about the additional expenses teleworking policies ] 之前的内容作表语 （倒装并省略了 it ）might incur 系动词 as （引导比较状语从句） staff start charging their home phone bills to the business. 做 it的同位语。

While company managers have known about the benefits for a long time, 为状语从句 many have done little about it 为主句，其中， company managers （条件状语从句主语） have known about （状语从句谓语） the benefits for a long time （从句宾语）, many（代词，代 many managers作主语） have done （谓语）little （宾语）about it （双宾语）。

之后的主句实际是个省略了 it 的倒装句， 应该是 it （主语）might incur（系动词） sceptical of whether they could trust their employees to work to full capacity without supervision, or concerned about the additional expenses teleworking policies .
意思是 这可能招惹（招致）怀疑他们是否可以相信他们的雇员在不受监督的情况下时可以全负荷工作，或招致对他们远程办公政策的附加（多余）支出的关注。

sceptical of （之后是宾语从句，即 of ... 介宾短语）whether they （宾语从句主语）could trust （宾语从句谓语）their employees （宾语从句宾语） to work to full capacity without supervision（为不定式做状语或补语）, or concerned about （过去分词做表语与sceptical of ...并列）the additional expenses teleworking policies (concerned about 的宾语) ] 之前全部部分作表语 might incur 系动词 as （引导比较状语） staff start charging （现在分词做状语） their home phone bills to the business. 整个句子作 it 的同位语。

全句翻译是： 当（因为）公司的管理层知道这样做的好处有很长一段时间时，很多管理层对招致他们怀疑是否可以相信他们的雇员在不受监督的情况下时可以全负荷工作，或招致他们关注远程办公政策的附加（多余）支出（的情况），比如员工将自己的家庭电话费用放在办公费用里， 这样的情况不作处理。

因为 sceptical （形容词）和 concerned about （过去分词）是形容词性，只可能作 定语或者表语，而如果作为定语则没有修饰的内容，而 incur 有实意动词作系动词用法，所以，这里是 incur 的表语。而该句子是倒装句，省略了形式主语it 所以应该理解为一个完整句。 而该完整句为 many have done little about it 中 it 的内容，即 it 的同位语从句。

sceptical of whether they could trust their employees to work to full capacity without supervision, or concerned about the additional expenses teleworking policies might incur as staff start charging their home phone bills to the business.整个结构做主语many的补足语，其中or前后连接的是对称的结构。whether they could trust their employees to work to full capacity without supervision作介词of的宾语。teleworking policies might incur as staff start charging their home phone bills to the business是修饰expenses的定语从句，而它本身又是带状语从句的复合句。

直译：
公司管理者们已经知道这个福利很长时间了，但很少人会付诸实施，怀疑他们是否能信任他们的下属完全在无监管的情况下满负荷工作，或者说担心这种远程办公政策（在家办公政策）可能导致附加费用，比如员工将自己的家庭电话费用放在办公费用里。

英文原文链接：http://www.guardian.co.uk/technology/2005/may/26/businesssolutionssupplement3

Rising costs of office space, time lost to stressful commuting, and a slow recognition that workers have lives beyond the office - all are strong arguments for letting staff work from home.

For the small business, there are additional benefits too - staff are more productive, and happier, enabling firms to keep their headcounts and their recruitment costs to a minimum. It can also provide competitive advantage, especially when small businesses want to attract new staff but don't have the budget to offer huge salaries.

While company managers have known about the benefits for a long time, many have done little about it, sceptical of whether they could trust their employees to work to full capacity without supervision, or concerned about the additional expenses teleworking policies might incur as staff start charging their home phone bills to the business.
...

[词义]
sceptical: tending to disagree with what other people tell you
搭配：sceptical about/of
例句: Envronmental groups are sceptical of the government's claims.

teleworking: working from home, and conmmunicating with the employers, customers etc using a computer, telephone居家办公

incur
if you incur a cost, debt, or a fine, you have to pay money because of something you have done
搭配：incur expenses/costs/losses/debts
If the council loses the appeal, it will incur all the legal costs.

work to full capacity v. 全力以赴

charging their home phone bills to the business由公司支付他们家里的电话费

[结构]
While company managers have known about the benefits for a long time, many have done little about it, [(who are) sceptical of whether they could trust their employees to work to full capacity without supervision], or [(who are) concerned about the additional expenses teleworking policies might incur as staff start charging their home phone bills to the business].

while引导让步状语从句从句，表示尽管。
主干： many (company managers) have done little about it
the additional expenses teleworking policies might incur将the additional expenses宾语前置，顺序：teleworking policies might incur the additional expenses居家办公可能引起额外的花费。

问：莫不是”sceptical of whether their employees will work to full capacity without supervision“
答：句子省略了who are, sceptical of和concerned about的主语是many (company managers)，两者为并列关系。可以理解为以下两个句子。
Many are sceptical of whether they could trust their employees to work to full capacity without supervision.
Many are concerned about the additional expenses teleworking policies might incur as staff start charging their home phone bills to the business.
他们怀疑是否能够相信在无人监管的情况下员工能全力以赴地工作

[译文]
尽管公司管理人员很早就知道这个利益，但他们并没有为此采取措施，他们怀疑是否能够相信在无人监管的情况下员工能全力以赴地工作，或者担心居家办公可能引起的额外花费，比如公司要支付员工家里的电话费。