1. b. Past Tense "sent" is changed into Past Perfect "she had sent"; the pronoun "I" changes to "she"; "this morning" changes into "that morning".
2. b. The negative imperative is changed into "tell + not + infinitive"
3. b. Present Progressive (continuous) is changed into Past Progressive (continuous); the "yes/no" type of question is reported by using "ask + if/whether + clause"