问题
选择题
The experiment shows that proper amounts of exercise, if regularly, can improve our health.
A．being carried out
B．carried out
C．carrying out
D．to carry out
答案
答案：B
这题考查if条件句的省略式，如果主从句的主语一样，可以省略从句中的主语和be动词。If carried out="if" the experiment is carried out..,句意是：这个实验表明，适当的锻炼，如果定期实施，对健康是有利的。选B。