Question

Denise accidentally deleted a sentence from her document. How can she replace it without retyping it?

Answer 1

she can click on the undo button located depending on the program she is using. (ms word: on the top left corner) 
or she can hold the ctrl button on her keyboard while she is pressing the z letter.

Answer 2

she can click in the undo/ redo button in the left corner of her screen