Actually, as you may guess, I'm not a native English speaker, in fact it's third language that I've leaned. Persian and Azari Turkish are my mother tongues. By the way, I have to get an IELTS cert and I should prepare myself to do so. But I have problem with tenses. I always get confused about perfect tenses. I really can't know whether I should use simple present/past or present/past perfect. I'm looking for some sort of flowcharts to check which tense should be used. For example I think I should use simple past when there is a "certain time", e.g. "yesterday" or "on March 9th". Could you please help me understand usage of perfect tenses. Here are some sentences you may use to explain the situation:
Concorde, the world’s fastest passenger plane, (develop) ____ by France and Britain together.
In the 1950s, both countries dreamed of having a supersonic plane, and the project (start) ____ in 1962.
£1.5 billion (spend) ____ on developing the Concorde, and it (test) ____ for over 5.000 hours, which makes it the most tested plane in history.
The first passenger plane (introduce) ____ by British Airways and Air France in 1976.
I know these are passive voices, but that's not the thing I'm talking about. Thank you in advance.