This is another set of prepositions often confused by ESL students. Since means ‘from a point of time in the past’. It is used with the present perfect tense of the verb.

• He has been absent since last Friday.
• It has been raining since yesterday.

Don’t say ‘He is absent since last Friday’ or ‘It is raining since yesterday’.

For is used when you refer to a period of time and not a point of time.

• It has been raining for two days.
• We have been waiting for ages.

A common mistake is to use since when referring to a period of time. You must not say ‘I have been waiting since two hours’ or ‘It has been raining since 2 hours’.

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1. Beside and Besides