Those old men often go bike riding.That has much more fun than staying at home中的staying要加ing 呢

题目

Those old men often go bike riding.That has much more fun than staying at home中的staying要加ing 呢

答案

因为这里的that是代替go bike riding短语,而此短语为动词短语,作主语应改成动名词短语,所以加ing