選D.這里是要按主句的,沒錯.
但不是所有情況下都是按主句的,具體是根據(jù)邏輯確定到底要對什么進(jìn)行反問.就這個句子的邏輯來講,上面的說話的人和聽的人都應(yīng)該知道he left his English這件事的,所以不需要反問這個.但是如果句子改成這樣就不同了：
I think he has left his English.
就這里的邏輯來講,就不能跟隨主句了,你不需要反問你是不是這樣認(rèn)為的,所以應(yīng)該是：
I think he has left his English,hasn't he?
如果改成這樣：
He thought she had left her English.就跟隨主句或從句都符合邏輯了.試比較：
He thought she had left her English,didn't he?(他不是這樣認(rèn)為嗎?）
He thought she had left her English,hadn't she?(她沒有放棄英語嗎?)