the boy to school he was nine years old .的地方填什么a went,until b didn`t,untilcwon`t,until d didn`t go,until

the boy to school he was nine years old .的地方填什么a went,until b didn`t,untilcwon`t,until d didn`t go,until
the boy to school he was nine years old .的地方填什么a went,until b didn`t,until
cwon`t,until d didn`t go,until

the boy to school he was nine years old .的地方填什么a went,until b didn`t,untilcwon`t,until d didn`t go,until
d didn`t go,until
the boy didn't go to school until he was nine years old .
男孩直到9岁才上学.
考察的是
not .until.
直到.才.

d didn`t go,until
the boy didn't go to school until he was nine years old .
男孩直到9岁才上学。
考察的是
not 。。。until。。。
直到。。。才。

didn't until
not until 是一个固定用法，表示“直到。。。才。。。”
在此，“这个男孩直到9岁才上学”

b didn`t go,until
楼主丢了个单词吧