The form is:
affirmative: Verb 得 de [Potential Complement]
negative: Verb 不 bu [Potential Complement]
Which potential complement to use depends on the verb.
It is easier to understand by looking at examples:
那个箱子重得拿不动。 Nàge xiāngzi zhòng de nábudòng.
‘That suitcase is too heavy to carry.’
So 拿 ná 'carry' takes the potential complement 动 dòng to produce 'can carry'.
There may be some exceptions to this rule, but most resultative complements and directional complements may be turned into potential complements by inserting 得 de after the first character (or 不 bu for the negative form).
from Centre for Teaching Chinese as a Foreign Language, University of Oxford.