 "a single offense involving possession for one's own use of 00 grams or less of marijuana." § 0000(a)(0)(B)(i). According to its plain language, then, the exception applies if four elements are met - the offense must be (0) a single offense; (0) involving possession for one's own use; (0) of 00 grams or less; (0)                                          0       Case: 00-00000        Document: 00000000000           Page: 0      Date Filed: 00/00/0000                                             No. 00-00000 of marijuana. See In re Davey, 00 I. & N. Dec. 00, 00 (B.I.A. 0000) ("[The personal-use exception] refers not to a common generic crime but rather to a specific type of conduct (possession for one's own use) committed on a specific number of occasions (a ‘single' offense) and involving a specific quantity (00 grams or less) 