I think doing exercises is good for health 这句话谁是主语 为什么

I think doing exercises is good for health 这句话谁是主语 为什么 I think doing more exercises is a good sport for students.请问 Doing more exercises( )(填is或are) good for our health 完形填空Doing morning exercises is good for our health.Every mor doing morning exercises --------(be) good for our health This book is too much for a child.这句话谁是主语,谁是表语,为什么? I think drink milk is good for your health 错在那里,为什么 i think walking is good for my health walking为什么加ing I think ____(do) exercise is good for health I think walking is good for our health 翻译 Doing morning exercises is good for you .句首为什么用doing?谢谢 （ ） morning exercises is good for our health.(do)