This exercise is to get students thinking about which punctuation fits best, a period or exclamation point. I like to tell students that we use exclamation points to tell a sentence that is exciting.
When teaching this exercise, the students read the sentences with me. I asked which punctuation fits best, period or exclamation point? If you think it is a period, show a closed hand. If you think it is an exclamation point, put your arm up. Then I reveal which one fits better and we all write it in. Students can write in their own sentence with correct punctuation at the bottom of the sheet.