The World English answer key often accepts two correct answers when both tenses are grammatically possible (e.g., habit vs. right now).
Is there a or grammar point you are struggling with? World English 2 Third Edition Answer Key
If you are a student: use the answer key not to finish faster, but to learn deeper. If you are a teacher: consider controlled release of answer keys to promote autonomy without enabling shortcuts. The World English answer key often accepts two