> Ankaŭ mi ne scias tion.

"Tion" is nesessary?

Imho not really... But "ankaŭ" must be in front of "mi".

Teorie vi pravas PaulP sed en www.tekstaro.com mi trovis 11 trafojn por "mi ankaŭ ne" kaj 14 trafojn por "ankaŭ mi ne"".

Zamenhof diris ke se oni volas esti tro logika la lingvo fariĝos malfleksebla.

@Selena
You have asked whether "tion" is necessary.
Imagine for a moment that you leave "the house of your mother tongue". Make a few steps aside. Now you may note that also the Russian sentence contains the idea of that what is known or not known. In Esperanto this is expressed by "tio". The Russian sentence doesn't lack this idea either even if we see no explicit expression of it.
Should it remain unexpressed in Esperanto? Would that be an advantage or an disadvantage for a language created and applied with the ambition that it should be as easy and clearly as possible understood all over the world?
You mentioned only hours ago that you felt a lack of rules in Esperanto. I can assure you: Esperanto allows you more freedom of expression than many, maybe even all other languages. But don't be afraid — there are some very important basic principles that rule Esperanto and they have to be quite severely observed of everybody who wants to use really good Esperanto. And the better we understand and apply these basic severe rules of Esperanto, the more we can enjoy and use with instinctive certainty the freedom that lies beyond these rules — more precisely the freedom made possible by this rules.
The verb is the central element in the structure and function of Esperanto, and a crucial point is the difference between transitive and intransitive verbs. A transitive verb can't do without an object. Take it as a rule to name it even than when other languages omit it. There are only few cases where we may sometimes omit the object of an transitive verb in Esperanto. 1. If the context of a dialogue makes absolutely clear what is the object. 2. If a specific situation allows that. (For example, when we say "Ni manĝos en la ĝardeno.", we know quite well what kind of food we usual eat and can do without specifying information.)
By the way, that's not a trivial topic at all for nations which languages don't draw a clear line between transitive and intransitive verbs. There lies one more reason for the recomendation not to omit the object of a transitive verb. This applies not only here; the more we allow a tendency of sloppiness, the more difficult orientation and learning will become.

@Alexander
Thanks for your explanation.
So it should alwayys be "Mi trinkas tion", "Mi manĝas tion", ect?

I've mentioned that a few verbs like "manĝi" and trinki" are plausible even without naming the object. Nevertheless, it's not a bad idea if you prefere a complete expression like "Trinku ion!"; "Ĉu vi nenion manĝis?", where it would be sufficent to write "Trinku!"; "Ĉu vi ne manĝis?".

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