What are the biblical allusions in A Tale of Two Cities for chapters 15,16,17,18,19,20, and 21?
And how do they connect or represent with the bible?

If you have not read this book yet, which it does not sound like it, start by reading it. Then come and ask your homework questions. If you absolutely need a cheat, then go to SparkNotes: Today's Most Popular Study Guides

Well.. I am reading the book!
I'm just not good with biblical allusions..
And I already tried sparknotes and they didn't give me biblical allusions

There is another post almost identical to yours - that post listed the Bibilical Allusions.