What does your sister usually do at nine o'clock?
sister是第三人称单数,用助动词does,助动词后用动词原型。
你姐姐通常在9点干什么
What does your sister usually do at 9 o'clock?
sister是第三人称单数,用助动词does,助动词后用动词原型What
does
your
sister
usually
do
at
nine
o'clock
what
does
your
sisiter
usually
do
at
nine
o'clock?