Thanee said:Of course it can.
"A staff is a long shaft of wood that stores several spells."
This sentence indicates that staves require a minimum of three spells in them (three generally being the minimum definition of the word "several").
Now, this does not mean that a staff might not only be capable of casting a single spell (e.g. in the case that one spell needs one charge and the other spells need two charges and there is only one charge remaining), but the staff still has a minimum of three different spells in it (regardless of whether they can still be cast).
Now, having said that, someone could loosely define "several" as allowing two, but definitely not one. It is apparent that WotC did this with the Staves of Charming and Life, each of which only has two spells in them.
So, it seems that WotC meant a minimum of two spells per staff because they used the phrase "that stores several spells" and gave examples of staves with two spells in them.