Questions & Answers about Я прошу тебя, чтобы ты не терял терпения.
Why is it терпения (Genitive) instead of терпение (Accusative)?
This is the Genitive of negation, which is the main topic of this lesson! The verb терять (to lose) normally takes an Accusative direct object. However, because it is negated (не терял) and the object is an abstract concept (patience), Russian strongly prefers using the Genitive case терпения.
Why is the verb терял in the past tense if I am asking you not to lose patience right now?
This is because of the word чтобы. When you use чтобы to express a request, wish, or purpose, the verb that follows it must be in the past tense (or an infinitive), no matter when the action actually takes place.
Why do we use тебя after прошу instead of the Dative case тебе?
The verb просить (to ask for, to request) takes a direct object in the Accusative case for the person you are asking. Therefore, we use тебя, which is the Accusative form of ты. Don't confuse this with communication verbs like говорить (to tell) or отвечать (to answer), which take the Dative.
If I take away the не, does терпения stay in the Genitive case?
No, if you remove the negation, the verb goes back to taking a standard Accusative direct object. So, if you wanted to say 'you are losing patience', it would be ты теряешь терпение. The Genitive терпения is strictly triggered here by the не.