Final answer:
The adverb in the sentence is 'well', which describes how the lessons have been done. It is a word that modifies the verb 'done' and is an example of how logical deduction can be used to infer actions from consequences.
Step-by-step explanation:
The adverb in the sentence "Today you have not done your lessons well" is well. An adverb is a word that modifies a verb, an adjective, or another adverb, telling us how, when, where, or to what extent. In the sentence provided, the adverb “well” describes the verb “done”, indicating the manner in which the lessons have been performed.
Using a similar logical structure as in the example provided, if it's known that Jad doesn't finish his homework on time, he won't go to the party, and it's observed that Jad doesn’t go to the party, then one can deduce that Jad didn't finish his homework on time. This form of reasoning is commonly used in logical arguments to draw conclusions from established premises.