Final answer:
To add the suffix ed to words ending in y, you generally change y to i, thus 'Hurry' changes to 'hurried'. 'Writing a note to a friend' is an appropriate situation for using text speak. The correct grammar for the comic books is 'The boys' comic books are on the teacher's desk.', and 'Certain' changes to 'certainly' when forming an adverb.
Step-by-step explanation:
Rules for Adding Suffixes to Words:
When adding the suffix ed to words, if the base word ends in y, and the y is preceded by a consonant, the y changes to i before adding ed. In this case, 'Hurry' becomes hurried. The other words (Betray, Destroy, Obey) do not require the y to be changed to i when adding ed.
In communication, shortcuts and "text speak" are most appropriate in casual settings, such as when writing a note to a friend. It would not be appropriate for formal situations like answering essays on exams, completing a job application, or emailing a teacher for help.
The correct grammar to describe the situation with the comics is 'The boys' comic books are on the teacher's desk.' It indicates that the comic books belonging to all three boys are on the desk.
For turning words into adverbs, 'Certain' will require the addition of ally instead of ly, making it certainly. The other words simply take ly to form the adverb.