问题
选择题
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
答案：C
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。