Mary spends one hour doing exercise every day.对one hour提问___ ___ ___does Mary speng doing exercises every day?
问题描述：
Mary spends one hour doing exercise every day.对one hour提问
___ ___ ___does Mary speng doing exercises every day?
答
how long.
是三个空how many hours.
how long does/how many hours Mary spend doing exercises every day？
答
How many hours