The sentence that best corrects the original is: She knew the answer but didn't speak.
Explanation:
Thus, "She knew the answer but didn't speak" correctly uses the past simple tense for both actions, aligning them appropriately in time.
Choose the correct option to fill in the blank: She is good ………….. mathematics.
Rearrange the following parts to form a meaningful and grammatically correct sentence:
P. that maintaining a positive attitude
Q. even in difficult situations
R. is essential for success
S. and helps overcome obstacles effectively