I wonder if once a week can be used at the beginning of the sentence and if yes, whether it should be followed with a comma. I tried browsing the Internet and Oxford Advanced Learner's Dictionary, but I haven't found examples with once a week used at the beginning of a sentence.
Is the following sentence correct?
Once a week, my sister and I go to a dance club.
READING WITH UNDERSTANDING, Intermediate 2 - Book 1 - Page 5 https://books.google.com/books?isbn=979413175X K. Methold - 1969 - Preview «Once a week I will get up in the middle of the night and shout «Stop, thief! Stop, thief !» The police will come. Everyone will think I am a good watchman». And this is what he did. For six nights a week he slept all night, but on the seventh night he got up and shouted «Stop, thief! Stop, thief!» and blew his whistle. The police soon came and said, «Where is the thief, old _nian?» «I frightened him away», the old man said. «You are a good watchman and you are brave», the police said ...
Once a Cop, Always a Cop: Why Me? - Page 33 https://books.google.com/books?isbn=1452591288 Lawrence LaRose - 2014 - Preview Some people illegally crossed over into neighboring countries like Surinam, Venezuela and Brazil in the hours of darkness, in purchasing band goods. Our household did not miss these band items. The canned goods were not frequently bought by my parents. And we survived off of farinaceous meals as: rice; flour; sago; cassava and various types of ground provisions from mom's kitchen garden. Once a week my dad on his way home from the night shift will bring home fresh fish from ...
