No you don't unless it's at the end of a sentence.
it was the period after the civil war when we were rebuilding our country
Since you didn't tell us what "this time period" might be, we cannot answer the question.
The Reconstruction Era was the period of time that began after the US Civil War. The plans to reunite the USA were controversial and bitter.
they ate choclate
the era of reform
You put a period at the end of the sentence to indicate that the sentence has ended.
No. You put only one period.
If a US president is going to be put under anesthetic for a period of time, the position is transferred to the vice president for that period. The vice president becomes the acting president.
put the patch on the Sunday after you start your period
Yes, you do put a period after "et al." in citations.
yes because if you dont it would be considered a run on sentence. Also if you decide not to it would be wrong and a person from the U.S. will look at you like your crazy and you would get laughed at and you dont want that to happen.
Yes, it is common to put a period after "Mrs." as it is an abbreviation for "missus."
no matter what you usually have to put a period after an apostrophe because it's the end of a sentence.
Yes there should be a period.
At the end of this sentence we had to put a period.
No you don't.
No, the initials US do not have to have a period. It is common to see "US" written without a period in modern usage.