Punctuation marks serve many functions. In ending a sentence, they tell us that it's time to stop and begin a new thought (and a new sentence). Usually, we can use a period, a question mark, or an exclamation mark to end a sentence.
We use a period to show the end of a declarative sentence: I have finished with my homework. Tomorrow, we are going to the movies. These are complete sentences, and the period goes at the end, to show that this sentence is finished. We use a question mark when we are asking about something, or we need more information. Did she get accepted to college? May I borrow your dictionary? And then, there's the exclamation mark-- it tells us the sentence is expressing excitement of some kind. I can't believe I passed the exam! Don't say those terrible things to me!
Any end punctuation will work depending on the sentence.
Write your sentence (then your parenthetical). Use the same punctuation inside the parentheses as you would outside of them and end the sentence with an ending punctuation mark (period).
Ending punctuation will depend on how the sentence is formed.
You typically need only capitalize after sentence-ending punctuation, which a hyphen is not.
The end punctuation in a sentence with parentheses depends on the overall sentence structure. If the parentheses contain a complete sentence, the period goes inside the closing parenthesis. If the information in the parentheses is additional or clarifying, the ending punctuation goes outside the closing parenthesis.
No, you do not need to add an additional period after an acronym at the end of a sentence. The period in the acronym itself serves as the ending punctuation for the sentence.
A period would go inside parentheses to finish a complete sentence, but you always need sentence-ending punctuation outside of the parentheses.
Do I need to use a period after the abbreviation of the word etc.? What is the correct punctuation for ending a sentence with etc.?
Punctuation at the end of a sentence indicates a complete thought.
No, you do not put an extra period after "etc." since the period at the end of "etc." serves as the ending punctuation for the sentence.
The correct punctuation for that sentence would be: "They all sang 'Happy Birthday' before she cut the cake." This includes putting 'Happy Birthday' in quotation marks and ending the sentence with a period.
It would be: Yes, we can. (or more emphatically) Yes, we can!