Doing morning exercises is ···?

Doing morning exercises is ···? Sam is doing his morning exercises.（用morning exercises提问） Doing morning exercises is good for us.（同义句） Doing morning exercises is good for us.(同义句) ____ we is doing morning exercises on the playground Ben ( ) morning exercises now.A do B does C doing D is doing Doing morning exercises is good for you .句首为什么用doing?谢谢 doing eye exercises and morning exercises (be) good for heal Kitty is doing morning exercises.She wants to keep herself f 小学英语句型转换doing morning exercises is good for us(同义句转换)______d Doing morning _____(exercises\exercise)is a good way to keep ()morning exercises is good ()you.a:doing,for.b:do,for.c:doi