Hey everyone! I’m currently studying for the ACT and I came across a question in my study books that I can’t seem to figure out:
After a short illness, Marta was again back in the office, she worked 12-hour shifts without a break. (‘she worked’ is underlined)
A. NO CHANGE
B. to work (which is what I picked)
C. working (which is the right answer)
D. and while working
The book I have explains why C is the correct answer and why all the other choices are wrong, but I can’t seem to understand!
to work indicates an aim or a goal, as in Marta was again back in the office specifically to do work. On the other hand, working does not have such a connotation.
Yet even with this slight difference in meaning, both would be correct if the punctuation changed. For “to work” to be correct, there should be no comma, ie the sentence should be “Marta was again back in the office to work 12-hour shifts”. In its current state, with a comma, “working” is correct.
This is because a comma cannot split a sentence’s subject and verb. For example, in this sentence, if “to work” was used then the comma between “office” and “she” split the subject (Marta) and the verb (work), which is not correct. The only exception to this rule is if the verb is repeated before and after the comma.
“working” is not a verb so the comma here is correct.
Thank you so much!!! 
@mintish
No problem!!