Answer:1. The underlined words ("will", "should", "shall") are all modal verbs.2. They are positioned in the sentences as auxiliary verbs, typically before the main verb.a. The modal verb "shall" indicates simple futurity and obligation.Additional explanations:- "Will" expresses future possibility or invitation (e.g., "I will need some...").- "Should" expresses a sense of obligation or recommendation (e.g., "lest he should fail...").- "Shall" indicates simple futurity and obligation (e.g., "You, shall I teach you...").Note: Modal verbs have various functions, including expressing:- Obligation (must, should, ought to)- Necessity (need to)- Possibility (might, may)- Prohibition or disapproval (shouldn't, ought not)- Futurity (shall, will)