# set the alarm for six o'clock

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#### arueng

##### Senior Member
In order not to oversleep, I set the alarm for six o'clock.

Hi,
I wonder why it's "set the alarm for six o'clock" in the above rather than " ... at six o'clock?" Could you explain why? Thanks.

• #### Joelline

##### Senior Member
If you said, "I set the alarm at six o'clock," you would be saying that the time you actually performed the function of setting the clock was at 6 o'clock. When you say, "I set the alarm for six o'clock," you are saying that 6 o'clock is the time you want the alarm to ring to awaken you.

##### Senior Member
Joelline's explanation is correct... but I can understand the confusion because these two sentences have the same meaning:

Our appointment is for one o'clock.
Our appointment is at one o'clock.

So you might just want to memorize the phrase "set the alarm for."

#### Jinsey

##### New Member
Joelline's explanation is correct... but I can understand the confusion because these two sentences have the same meaning:

Our appointment is for one o'clock.
Our appointment is at one o'clock.

So you might just want to memorize the phrase "set the alarm for."
It is beyond me too. What's the main difference between those both sentences?