"They were doing an experiment" is past tense.
The past tense of "scent" is "scented".
Solute isn't a verb and so doesn't have a past tense.
'separated three substances' is past tense.
The word "sublimation" is a noun and so doesn't have a past tense. Only verbs have tenses.
Condensate is primarily used as a noun. If it's being used as a verb the past tense is condensated.
The past tense of experiment is experimented.
The past tense of experiment is experimented.
are is for present tense for example, what are you doing and were is past tense what were you doing
The simple past tense is did. The past participle is done.
The simple past tense of "do" is "did". Example: When I was a child, I did not like to read books. I did You did He did She did We did You did They did
The past tense of do is did. "We did a lot of work today. "The future tense of do is:will do - I will do the washing tonight.be + going to do - I am going to do my homework tomorrow night.be + doing - I am doing my homework later.
Past tense: The cat chased the mouse. Present tense: The cat is chasing the mouse.
The past participle is done. The simple past tense is did. The present participle is doing.
Did is the simple past tense. The past participle is done. Instead of saying "I am doing this" you would say "I did this". The present perfect tense is "I have done this."
The verb in the sentence is 'are doing,' so the past perfect tense would be 'have done.'
The past tense of "I think you are doing well" would be "I thought you were doing well."
Did is past Do is present Doing is future.