they are in front of the building.（对划线部分提问）
问题描述：
they are in front of the building.（对划线部分提问）
答
划线在哪呀。地点用Where are they
答
若划线部分是in front of the building，答案为：Where are they?
若划线部分是they.答案为：Who are in front of the building?
答
where are they?