Cho hai đường thẳng vuông góc với nhau a và b. có bao nhiêu phép đối xứng trục biến a thành a biến b thành b?

A. Không có phép đối xứng nào

B. có một phép đối xứng trục duy nhất

C. Chỉ có hai phép đối xứng trục

D. Có vô số phép đối xứng trục

Mark the letter A, B, C, or D to indicate the sentence that is closest in meaning to each of the following question.

It was essential to persuade him to change his mind but you didn’t.

A. You should have persuaded him to change his mind.

B. You must have persuaded him to change his mind.

C. You should persuade him to change his mind.

D. You may persuade him to change his mind.