the annoy 'the'
Why use a 'the' before 2 and 3,but not before 1?
Technological innovations and mass production have reduced the cost of ( 1 uncountable noun ) production and improved the( 2 uncountable noun ) productivity of the ( 3 uncountable noun )workforce.

Question

the annoy 'the'
Why use a 'the' before 2 and 3,but not before 1?
Technological innovations and mass production have reduced the cost of (  1   uncountable noun   ) production and improved the(  2    uncountable noun      ) productivity of the (   3 uncountable noun        )workforce.

Answer

I'll do this in reverse order:

3. 'Workforce' is not an uncountable noun.  It is a singular noun referring to a group of people. That's why it needs an article.

2. 'Productivity' is part of the noun phrase 'the productivity of the workforce'. This refers to a particular productivity i.e. the productivity of a certain group of people. That's why it needs a definite article.

1. Production is an uncountable noun, so it can occur without an article. Here it refers to production in general, which is why there is no article used.

Answer

There is a 'the' for the first subject, but the first subject is "cost of production." Subject 1 (The cost of production), subject 2 (The productivity), subject 3 (The workforce). Hope this helps!