Explanation of when to use the prepositions for, while and during.

FOR
Use 'for' with a period of time to express the duration or 'how long' something has happened:

• for three weeks
• for many years

WHILE
Use 'while' plus a verb form:

• while I was watching TV
• while I lived in New York

DURING
Use 'during' with a noun to express 'when' something happens:

• during class
• during my vacation
• during the discussion

The grammar authorities are going to battle it out today. For they all have a different opinion about our topics: the merits of using the word “for” to mean “because,” and whether it’s OK to start a sentence with the word “for.”

Now, guest-writer Bonnie Trenga writes,

The experts' opinions range from,

• yes, go ahead and put a “for” wherever you like—in the middle or at the beginning of a sentence; to
•  yes, but “for” belongs best at the beginning of an independent clause; to
• no, no way—you’re not allowed to put “for” at the beginning of a sentence.

Yikes! Who’s right? You’re going to upset someone no matter what you do.

Some common rules for advance learners.