问题补充:
good for our health.
A. Do exercise is
B. Doing exercise is
C. Do exercises are
D. Doing exercises are
答案:
A. Do exercise is
(答案→)B. Doing exercise is
C. Do exercises are
D. Doing exercises are
解析:句意:做锻炼有利于我们的健康。do exercise做锻炼,exercise当锻炼时,是不可数名词,没有复数形式。be good for对……有好处;利于。此处作主语,故用动名词短语,动名词短语做主语,谓语用单数形式。故选B。