when_____Jenny and her sister usually____(go) to school?
问题描述：
when_____Jenny and her sister usually____(go) to school?
答
do go
答
When (do) Jenny and her sister usually (go) to school?
解释：
(1)因为“Jenny and her sister"是并列结构，是第三人称复数，因此”do"要用原形.
(2)因为有助动词“do"，因此”go"要用原形.
答
do go ； Jenny and her sister是双数
答
do
go
答
when do Jenny and her sister usually go(go) to school?
因为有usually,正常情况下都是一般现在时
答
do go
因为jenny和她的sister是两个人，主语是复数，所以是用do，所以后面用动词原形go