There appears to be several strings missing from the .pot available for https://translate.wordpress.org/projects/wp/3.5.x/en-gb/default according to the results returned from a search.
WP Core contains strings like “This comment is in the Trash. Please move it out of the Trash if you want to edit it.”, “Trash Comment”, “This comment is currently in the Trash.”, and “You are about to move the following comment to the Trash” etc. but the search for the term “trash” with Any status (https://translate.wordpress.org/projects/wp/3.5.x/en-gb/default?filters%5Bterm%5D=trash&filters%5Buser_login%5D=&filters%5Bstatus%5D=either&filter=Filter&sort%5Bby%5D=priority&sort%5Bhow%5D=desc) doesn’t show these.
There well may be other strings that aren’t listed for translation, but this is all the detailed digging I’ve done so far.