此时/彼时怎么说?on this/that occasion?

on this occasion 、on one occasion、on another occasion、on the on this occasion,I'd like to say that we are__much grateful “此时流泪,彼时花开. on this occasion,on this moment的区别 occasion that 和 occasion when On this special occasion I’d like to express my 英语翻译On this occasion,however,it had slowed down considerably 此时流泪彼时开花的意思 on occasion是什么意思 On the occasion 英语翻译用on...occasion on _____ occasion = in this situation?空格里填什么?还是不填?