windows phone voice command syntax - windows-phone-8

Question

I wonted to know is there any way to have optional Phrase in windows phone 8 voice commands.
I mean something like this:
<Command Name="actoin">
<Example>he goes to school</Example>
<ListenFor> he goes to school [{with}] [{time}] </ListenFor>
<Feedback>ok!</Feedback>
<Navigate Target="MainPage.xaml"/>
</Command>
<PhraseList Label="with">
<Item>by bus</Item>
<Item>by tax</Item>
<Item>by his father</Item>
</PhraseList>
<PhraseList Label="time">
<Item>sometimes</Item>
<Item>always<Item>
</PhraseList>
actually i want to make with and time optional and avoid writing a separate command for each combination of them!
thanks

Answer 1

You can have multiple <ListenFor> elements (up to 10) per command; you could build the options that way.
For example:
<Command Name="action">
<Example>he goes to school</Example>
<ListenFor> he goes to school {with} {time} </ListenFor>
<ListenFor> he goes to school {time} </ListenFor>
<ListenFor> he goes to school {with} </ListenFor>
<ListenFor> he goes to school </ListenFor>
<Feedback>ok!</Feedback>
<Navigate Target="MainPage.xaml"/>
</Command>
<PhraseList Label="with">
<Item>by bus</Item>
<Item>by tax</Item>
<Item>by his father</Item>
</PhraseList>
<PhraseList Label="time">
<Item>sometimes</Item>
<Item>always<Item>
</PhraseList>