As we all know exercise will help to strengthen the heart and improve circulation of the

问题补充：

As we all know, exercise will help to strengthen the heart and improve circulation of the blood.

A. normal

B. average

C. regular

D. ordinary

答案：

A. normal

B. average

(答案→)C. regular

D. ordinary

解析：句意：众所周知，定期的锻炼有助于增强心脏，促进血液循环。 regular定期的，有规律的。故选C。