Your time is appreciated.
First off check your daily budget and your CPC.If they are too low your ads don't appear.
Second,check if your keywords are not pending a review.
Some particular "sensitive"keywords in fact has to be reviewed before publication.
At last, verify the number of clicks.
If the daily budget is not adequate,your ads could disappear after a certain number of clicks and be published with "intermittence".This is normal and requires only a budget review.
Hope to be useful.
Most common reasons ads aren't showing:
[webmasterworld.com...]