Chinese Translation Help?

I have a show-cancelled souvenir card from ROCPEX 78 in Taipei, with two handstamp cancellations. I'm trying to determine what these say, to see if this particular card was issued by an individual stamp club. Any assistance is welcome!

The souvenir card itself is a USPS production. Similar ones were created for major US and international stamp shows they attended.

You're correct. And there was no official translation for the text on the USPS card, as originally issued. However, on certain show cancelled cards there was a rubber stamp added on the back with translated text. It would appear that whatever group cancelled these particular cards also added the back stamp. I'm hoping if we can decipher the show cancels maybe it will ID the group.

The black cancellation on the left: based on the Chinese characters at the top, it is the exhibition commemorative cancellation. It is dated "67.3.20", which translates to March 20, 1978 - the first day of the exhibition. The characters at the bottom read 'Taipei temporary post office'.

A last-day cancellation, on a Taiwan souvenir cover, can be seen here on the Bay --> https://www.ebay.com/itm/3943487056...9SR9yiiPyaYQ

The purple cancellation on the right just says something along the lines of commemorating the exhibition, Taipei, March 20-29, year 67.

Thanks, Prexie! That is helpful, although it doesn't really give me my answer. We may not be able to pin down who added the back stamp.