The empty alternative can appear in a Normalized policy in conjunction with other non-empty alternatives. It simply states that taking no action is a valid choice.
空替代出现在标准化策略中用来连接其它非空策略，它只是说明不采用任何行动是正确的。
2
So Oxford Nanopore has also been looking at an alternative approach, called exonuclease sequencing, in conjunction with Illumina, an American firm that is the market leader in rapid sequencing.
The present author aims to discuss primarily on the global warming issue in conjunction with the optimum selection of alternative refrigerants for various application of refrigeration technology.