Can it be present tense also?
Scrutinise could be present or last tense. My answer should be accepted.
Oración can also be speech. I was marked wrong so I reported
That would be a very elaborate way to say 'speech', just stick to 'sentence', and use discurso for 'speech'.
If the verb conjugation is the same, how would we know if it's past or present when there is no time context?
From the time context. :)
English does it, too, with some verbs. "I read many books." Do you still read them or not? "We cut the grass once a week." Do you still do that?