28.It took her ten hours to learn to ride a bicycle .(同义句)

It took her ten hours to learn to ride a bicycle .(同义句)
She______ten hours _____ to ride a bicycle .
答案：
she spent ten hours in learning to ride a bicycle
因为hours后只有一个空格,我不晓得答案是不是符合要求.
再问： 那一个空该填什么
再答： 填study试试