They saw a Beijing opear last week.对last week提问 ___ __ __ they___a Beijing opear?

问题描述:

They saw a Beijing opear last week.对last week提问 ___ __ __ they___a Beijing opear?

What time did they see a Beijing opera?
如果前面是两个空的话,就是
When did they see a Beijing opera?
不知是否明白了\(^o^)/~