iPhoto11 will not assign keywords

I have just opened iPhoto 11 on my new iMac27 with Lion. I tried assigning keywords following the instructons carefully, but they never appear below the photos. I used to do this easily with earlier versions of iPhoto. Previously-assigned keywords are still there, and th new words appear in the index list, but are not with the photos. I can alter the image # to add descriptions on the titles, but why can't I use the keyword assign function? Any ideas please?

Thank you , Keith