"If you don't know mushrooms, you should not pick them."
Translation:Když neznáš houby, neměl bys je sbírat.
'Jestli neznáš houby, ty bys je neměl sbírat.' (Why) Is the 'ty' in this sentence necessary?
Díky za rychlou odpověd'! I thought the same way. The translated sentence beginning with 'Když' doesn't demand 'ty', but the sentence beginning with 'Jestli' claims it wrong, when the 'ty' is missing. Maybe a not yet added right answer?
Well, what i see in the back is that somebody suggested "jestli neznáš houby, bys je neměl sbírat" two hours ago. You cannot say that. Either you insert TY in front of BYS or you change the order to "..., neměl bys je sbírat". You cannot start a sentence (even a side sentence) with a condition like this.