I'm so glad to see you back,Lucy.How long _________at your grandma's?A. had you stayed B.did you stay C. have you stayed D.would you stay 请问选什么?谢谢

I'm so glad to see you back,Lucy.How long _________at your grandma's?A. had you stayed B.did you stay C. have you stayed D.would you stay 请问选什么?谢谢
I'm so glad to see you back,Lucy.How long _________at your grandma's?
A. had you stayed B.did you stay C. have you stayed D.would you stay
请问选什么?谢谢

I'm so glad to see you back,Lucy.How long _________at your grandma's?A. had you stayed B.did you stay C. have you stayed D.would you stay 请问选什么?谢谢
B

D

A
I'm so glad to see you back,Lucy.How long ____had you stayed _____at your grandma's?
从句子中看，呆在祖母家是一件过去发生的是，所以要用过去式，但是有是问呆了多久，强调一个持续性的过程，所以要用过去完成时
祝你学习顺利，请采纳

选C，how long 多长时间，提问的是一个时间段，故应该用完成时态，主句是一般现在时，故从句应该用现在完成时。