It can, however, become confusing when the preposition is understood. In the sentence, She did that herself, it is understood that a preposition precedes herself. With the elliptical preposition in place, the sentence might read She did that BY herself. Note that these instances are with objects of prepositions that are used in adverbial phrases. The phrases answer the question how.
Adverbs can also answer the questions when, where, and why.
Reflexive tense is normally not used in sentences where the adverbial phrase answers any other question than how. For instance, it is not considered standard grammar to say He gave it to myself. He gave it to me. Here are some practice exercises. Write C by the sentences that are correct.