1 .We received this letter from Continental Equipment a week ago.
2.When we receive your confirmation, we will open the letter of credit.(аккредитив)
3.I want to test this equipment.
в скобках "инфинитив"
1 - received (receive). Past Simple (простое прошедшее)
2 - receive(receive), open (open). Future Simple (простое будущее)
3 - want(want), test(test). Present Simple (простое настоящее)