"Two years is too much time."
Translation:שנתיים זה יותר מדי זמן.
Well, Glinert in The Grammar of Modern Hebrew §16.3.6 gives the examples סוּפוֹת רְעָמִים (זֶה/זוֹ) תּוֹפָעָה מוּזָרָה thunderstorms are a strange phenomenon and רוֹפְאִים זֶה מִקְרֶה מְיֻחָד doctors are a special case and explains: זה and its feminine forms are also common (i.e. beside the forms of הוא) ... with an inanimate predicate (particulary where the subject too is inanimate). So זֶה agrees with זְמָן and not the subject שְׁנָתַ֫יִם (or זֶה is used regardless of the form of the predicate).
If you're trying to say These 2 years are too much time then you have to put ה in front of אלה and again in front of שנתיים and take away the copula (זה in this case).
השנתיים האלה יותר מדי זמן. (Can someone verify the grammar here?)
Otherwise, it's like this:
שנתיים הן יותר מדי זמן. Two years are too much time
But, I think we are dealing with a single PAIR of 2 years so that is why they put זה.