Who is reading? The grammar of the sentence tells us that "the explanation" is reading, but that is clearly impossible.

Correction: After I read the article, the explanation became clear.

In the corrected version we know who did the reading. For more on modification consult the LARC Electronic Writing Center grammar checklist.

Check the following resources for useful practice material: 1) Guide to Grammar and Writing, 2) Colleen Hildebrand's UCI Correction Symbols with hyperlinks.