Choose the most effective revision about the underlined part of the sentence. If no revision is necessary, choose leave it as it is. Mary Jean and Beth volunteer for the past five years at a local shelter for abused pets.

Mary Jean and Beth volunteered for the past five years at a local shelter for abused pets.

Explanation:

In the given sentence, the action/ verb is something that's done in the past. This is identified by the phrase "for the past five years", meaning it is an action that's been done in the past, that happened some years before the present.  Therefore, the verb "volunteer" will be used on the past form "volunteered".

So, the newly revised sentence will become-

Mary Jean and Beth volunteered for the past five years at a local shelter for abused pets.

answer: i would say he was very determined and persistent in overcoming obstacles.

explanation:   "the magician of menlo park" as he was called, liked to tell an incident that happened when he was 8 years old and came back home crying after attending school for three months because his teacher called him "sterile and unproductive". from nowadays perspective, we can say that thomas alva edison was one of the most persistent and determined man that has ever existed. when edison was 14, he contracted scarlet fever. the effect of the fever, as well as a blow to the head by an angry train conductor, caused edison to become completely deaf in his left ear, and 80-percent deaf in the other. so as you can see he had to struggle to not so many minor issues but he always succeeded.

she has clear pronunciation