The adsorption site strength of ammonia, oxygen and propylene in the fresh catalyst is weaker,and the adsorption site density is greater, so its catalytic activity is better.是什么意思_The adsorption site strength of ammonia, oxygen and propylene in the fresh catalyst is weaker,and the adsorption site density is greater, so its catalytic activity is better.在线翻译_英语_读音_用法_例句