the girl__a book in the garden ,while a boy ran to her.
问题描述：
the girl__a book in the garden ,while a boy ran to her.
答
was reading
应该用进行时，while表示一方干什么的时候，另一方在干什么。
后面是ran，所以应用过去式。
答
The girl was reading a book in the garden ,while a boy ran to her.
答
was reading