Hi,
Please tell me how they are different. I am not asking for the answers to the questions but rather, whether how the differences in forms affect their meaning.
1. Can an adverb modify a verb?
2. Can the adverb modify the verb?
3. Can a bear eat apples?
4. Can the bear eat apples?
I think when you are making a general statement, one of the typical articles to use is the; thus, when making a general statement, the forms shown in No.2 and No. 4 are what you need. Right?