Complete the sentence with “there is” or “there are” (Hoàn thành các câu với “there is” hoặc “there are”) I know … an answer to this problem, but I can't find it.

Complete the sentence with “there is” or “there are” (Hoàn thành các câu với “there is” hoặc “there are”)

I know … an answer to this problem, but I can't find it.