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.