Don't understand one sentence about masks

[mrnbdy]

I've been reading about mask_attack [hashcat wiki].

I'm reading the section titled "Masks". I understand it until the last dot point:

* A static letter is not indicated by a letter. An exception is if we want the static letter ? itself, which must be written as ??.

Can someone please explain what "a static letter is not indicated by a letter" means?

I thought if you knew part of a password you put those letters and didn't use the ? symbol before hand.
Eg. ?l?l?lpart?d?d
I thought this mask would try passwords with any 3 lowercase letters and any 2 numbers with the letters 'part' between them?

[Snoopy]

yeah this sentence seems to be a little bit misleading

your provided mask will indeed generate passwords like you want

hashcat -a3 --stdout ?l?l?lpart?d?d

qvopart72
mfopart72
czupart72
bxtpart72
aqmpart72
...
rkepart80
kbepart80
hdepart80
gcepart80
fjmpart80
nropart80

[mrnbdy]

Thank you very much. 

Would it be correct to say:

A static letter is not indicated by a preceding ?. An exception is if we want the static letter ? itself, which must be written as ??.

[Snoopy]

Thank you very much. 

Would it be correct to say:

A static letter is not indicated by a preceding ?. An exception is if we want the static letter ? itself, which must be written as ??.

yes