Sentence Correction

/Machines replacing human labor, there was wide anticipation that /the workweek would continue to become shorter

a,

c, as machines replaced human labor, it was widely anticipated that


A, or C is correct" and more importly, why

C is correct i think

A has a tense problem.
Machine replacing hmans --> happening now

there was wide anticipation that ---> that is in the past

C how ever is consistent( replaced , Anticipated)

no,

a, replacing" occure at the same time as "there war"

duongthang wrote:no,

a, replacing" occure at the same time as "there war"

Well you are right in your reasoning that replacing is happening at the same time as anticipating hence both should have the same tense
However in A the first part is in present tense and the second in past tense

Replacing in option A uses present tense

Im am replacing the book - this action is happening right now

'There was' is past tense

There was a dog outside my house

So in this question you have a sentence that starts in present tense but continues in past tense so there is no consistency in verb tense.

Hence C is right

If you are really looking for correct tense then B should strike first:

When machines replaced human labor, there was wide anticipation

any way I would like to know a concrete point for C to be correct.

in the absolute phrase, action happent simultaneouly with the action of main clause,

so, the tense is correct here

A is wrong because the 'there is..." is not so idiomatic as "it is ..."

but I am not sure