The coat on the chair is Helen's?对划线部分进行提问.is Helen's 提问.顺便讲下原因.

The coat on the chair is Helen's?对划线部分进行提问.is Helen's 提问.顺便讲下原因.
The coat on the chair is Helen's?
对划线部分进行提问.is Helen's 提问.
顺便讲下原因.

The coat on the chair is Helen's?对划线部分进行提问.is Helen's 提问.顺便讲下原因.
对is Helen's 提问,即“是海伦的”,这是英语所有格形式,海伦是人名,因此应用“whose”,后面应紧跟所说的名词,因此是whose coat,我的答案是：whose coat is it on the chair?或者说：whose coat is on the chair?

whose coat is it which one is on the chair? 对"谁的"提问要用whose

Whose is the coat on the chair?
先对物主词helen's 提问用Whose
在把后面的变成一般疑问句
所以is也提前

Whose is the coat on the chair?
这题对海伦的大衣提问应用“whose”，底下照样写

Whose is the coat on the chair?
对is Helen's 这个物主的提问，用whose，谁的。

Is the coat on the chair Helen's?疑问句的谓语提前

Whose is the coat on the chair?
Helen的衣服，所以用whose来提问。
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whose coat is it on the chair?

whose is the coat on the chair?
把helen's换成whose ,即所有格对应的疑问词，
其余照抄，whose 放到句首即可

The coat on the chair is whose.答案是it is Helen's对什么提问，答案就是你要提问的东西

Whose coat is it on the chair?

whose is the coat on the chair?
此处是对所有格提问 所以疑问词用whose
然后将后面的内容变成一般疑问句就可以了

Whose is the coat on the chair?

Whose is the coat on the chair?
对所有格提问,用whose.

whose's coat is on the chair