"I need this for Wednesday."
Translation:אני צריך את זה ליום רביעי.
From what I understand, בשביל means "for", in the sense od "for the sake of", so it would not work in this cobtext
Why does this one use -ל clitic preposition and, say, תודה על הזמן שלך uses על standalone preposition?
Prepositions are more or less arbitrary. To me, the "for" in "need it for" is different than the "for" in "thank you for". The former implies purpose, and the latter implies exchange, this for that. But that's me the non-native English speaker.
Thanks. Those would be two different prepositions in my native language as well. For some reason I thought "-ל" and "על" is the same preposition in the same way as "-מ" and "מן" are the same preposition in clitic and standalone forms.
At some point someone told me that צריך isn't a verb. Is this true? If so, why the direct object marker in a verbless sentence?
Well, צָרִיךְ is an Aramaic style verbal adjective (originally meaning needy), from the late Biblical literature (Sirach) and the Mishnaic time and for this type of adjective -ל was used for the compliment, of what you are needy. But it is (mis)used in Modern Hebrew in all layers of the language from poetry, journalism to common speech as capable of taking a direct object, probably under the influence of European verbs like to need something.