Plentifully tells you how something is given or happens: in a large amount, more than enough. Rain may fall plentifully. A garden may produce tomatoes plentifully. The word is correct, but it feels a little stiff, like a textbook adverb. In ordinary talk people say a lot, plenty, or in plenty instead. You will meet plentifully in careful writing more than on the playground. Though actually, you almost never need it once you know plenty and plentiful; it is just plentiful with -ly on the end, turning “there is a lot” into “in a lot-of way.”

充足地、豐富地