Doing morning exercises is a good habit.(改为同义句)—— ——a good habit —— ——morning exercise.

问题描述:

Doing morning exercises is a good habit.(改为同义句)
—— ——a good habit —— ——morning exercise.

这是讲动名词作主语改成IT作形式主语的结构就是It is a good habit to do morning exercise

(It) (is) a good habit (to) (do) morning exercises.