求翻译：而催化活性是由转化率和选择性共同决定的，因此，我们重点研究[PAC 18n]+[BF4]- 型离子液体催化合成乙酸松油酯的催化性能，从中筛选最佳催化剂。是什么意思？

The catalytic conversion and selectivity by joint decision, so we focus on [PAC 18n] + [BF4] - ionic liquid Synthesis terpinyl acetate catalytic properties, selected from the best catalyst.

The catalytic reactive is the conversion rate and selective common and, therefore, we focus on the research [PAC BF 18 N] + [ 4] -type ionic liquid catalytic synthetic acetic acid Ethyl pine oil filter from the catalytic performance, best catalyst.

But the catalytic activity is decides together by the conversion rate and the selectivity, therefore, our with emphasis research [PAC 18n] + the [BF4]- ion liquid catalysis synthesis ethanoic acid pine oil ester catalyzed performance, screens the best catalyst.

Catalyzed activity is decided by conversion and selectivity together, so our key research [PAC-18n]+[BF4]-ionic liquids catalyzed synthesis of terpinyl catalytic properties, filter best catalyst.

But the catalytic activity is decides together by the conversion rate and the selectivity, therefore, our with emphasis research [PAC 18n] + the [BF4]- ion liquid catalysis synthesis ethanoic acid pine oil ester catalyzed performance, screens the best catalyst.