what has sulfur been used in the past?what has sulfur been used in the past?
Yes it has been successful in the past
what has sulfur been used in the past?what has sulfur been used in the past?
Have been is present tense and had been is past tense.
Have been or Has been IS the past participle......it is equivalent to "was".
Yes it has been successful in the past
Have is used for present and Have been is used for past continous.
Used (e.g "It had been used for...", "John was used", etc.)
It is the past participle of "be," to exist.
"Been" is the past participle of the verb "be," used to indicate a state or condition that was present in the past.
"Would have been" is used to talk about hypothetical situations or events that did not happen in the past. It is used to describe unrealized possibilities or regrets about the past. It is not used to refer to events in the future.
"Have been" is used in present perfect tense to indicate an action that began in the past and continues to the present. "Had been" is used in past perfect tense to indicate an action that was completed before another past action or time.
Have been and has been are both forms of present perfect.Use have been for I and plural subjects egI have been to China. They have been to China. The doctors have been to China.Use has been for he/she/it and singular subjects eghe has been to China. The boy has been to China.Present perfect is used to talk about something that happened in the past but has result now or is important nowHad been is past perfect the same form is used for all subjects egHe has been to China. We had been to China The doctor had been to China.Past perfect is usually used to talk about something that happened in the past before another thing that happened in the past (past simple).eg He had been to China when I last saw him. - saw = past simple