I checked the PDF's and I'm not sure what you are asking The instruction are asking you to fill the blanks with "a" "an" or "the" where they are needed or to leave them blank. This can be tricky because some of the blanks you are not suppose to fill.: http://www.english-grammar.at/worksheets/articles/art2.pdf 34. ___the___ Milk is rich in ______ nutrients. The milk is rich in nutrients. This is the correct answer. Try not to get too confused. If you need any more help I am happy to help you. Just send me a message. Good luck with your studies.

I can tell you that all the answers in each answer key are correct. The first pdf has 40 sentences, and the second 37. Do you really want us to give you an explanation for each sentence? I suggest choosing one or two specific sentences which confuse you, and asking about those.