_____are you going to the airport A.How B.When

问题描述:

_____are you going to the airport A.How B.When

这道题应该还有上下文的.
如果没有上下文的话,how和when都可以.例如:
----When are you going to the airport?
----This evening.
---How are you going to the airport?
---By bus.