Another question popped into my head:
with regard to the time indication "all day ROUND", I don't know whether it's an expression or a fixed phrase. I searched on the internet, but I couldn't find it with "day".
Hi, Hussein: The normal, native expression is not "all day round"; it's "the whole day round." If you search for that phrase, you will reap a nice harvest of results.
If the question maker means "all day", why did he/she use it with the "past simple"?
Rachel on an earlier thread said, "all day, all morning, etc. use this especially when the day, morning, etc. has NOT FINISHED YET: We've been traveling around all week / I haven't seen her all day – where is she?"
I agree with Gustavo's answer. I'd also like to mention that it is perfectly fine to use the past simple in both clauses, to omit the repeated subject from the second clause, and to use "all day." You do not have to use "all the day" instead of "all day" if the period of time is completed. "All day" is correct in both cases. Native speakers rarely say "all the day" these days; it sounds old-fashioned. When we use "the" in this context, we generally say "the whole day" instead of "all the day," though both phrases are fine.
1a. I worked hard all day but failed to achieve my goals.
1b. I had worked hard all day but failed to achieve my goals.
1c. I worked hard the whole day but failed to achieve my goals.
1d. I had worked the whole day but failed to achieve my goals.
1e. Although I had worked hard the whole day, I failed to achieve my goals.
The past perfect is most advisable in the "although"-clause of the last example.