Where is your pen pal from?这边用的是is.那为什么What are your sister doing是用are呢?
问题描述：
Where is your pen pal from?这边用的是is.那为什么What are your sister doing是用are呢?
答
错了吧，应该是What is your sister doing.仔细看一下，有可能答案错了哟！
答
你可能看错了，可以是What are your sister do？你姐姐的职业是什么？
也许是What are your sister going to do?你的姐姐打算干什么？
但是What are your sister doing是病句
望采纳
答
What is your sister doing?
答
你弄错了吧，不可能是are只有what are you doing
答
因为What are your sister doing错了
What is your sister doing才对,你姐姐是第三人称单数