Student or Learner
I am writing my thesis now, it's about an U.S. airline, which ceased operation in 2010. For this reason, most of the sentences need to use past tenses. But it's really hard for me to use the Past Perfect tenses.
Most of articles explaining past perfect tense are using "before" or "after", for example,
A incident happened earlier than B incident, so A incident uses present perfect and B uses past tense.
But my situation is a little different, here are my questions:
1. Duration in the Past
A. Northwest Airlines had operated flights between the U.S. and Asia from 1947 to 2010. OR,
B. Northwest Airlines operated flights between the U.S. and Asia from 1947 to 2010.
A. The Second World War in the Pacific region ended in the mid-1945, since then, Japan had been occupied by the Allied Powers until 1952.
B. The Second World War in the Pacific region ended in the mid-1945, since then, Japan was occupied by the Allied Powers until 1952.
3. HAS/HAD NEVER
This sentence I want to explain that the airlines has never served flights to some cities, but Northwest airlines has closed down already. Do I change the sentence from present perfect to past perfect?
A. The company has neveroperated flights to those cities except Shanghai due to Chinese Civil War.
B. The company had never operated flights to those cities except Shanghai due to Chinese Civil War.
I really want to know how to use present perfect tenses in a right way. I asked some native speaker, but they told me that they know how to use it, but don't know how to explain to me...
Thank you very much!
1 Simply for duration, use the past tense.
2 Past tense, and use after that not since then. Also change the comma to a semi-colon or start a new sentence.
3 Use the past perfect or simple past- it's not clear which to me without more context. I would say the Chinese Civil War.