Two lovely young ladies have signed up for my AP Lit class next year who work hard and show great insights into the literature. They read well, but their writing leaves something to be desired. Both are Asian and ESL. Although born and raised in California, their parents' speak Mandarin at home (or maybe it's Cantonese), and their writing exhibits something other teachers at my school have called "the Chinese voice."(Subject-verb agreement, verb tenses, preposition difficulties, and unclear or missing pronoun antecedents are their main difficulties, but they also have others). I would love to have the gals in my AP Lit class, but I'm worried about their mechanics.

I would like to recommend a self-study or online grammar resource they might work with over the summer to shore up their skills. Do any of you know of such a thing? Or, could you recommend another way to help?