用does she
跟I think 這種不一樣,如果是I think Tom sings best in the class,就用doesn't he?
如果陳述句為含有賓語從句的主從復合句,反義疑問句的謂語動詞和主語代詞一般同主句的謂語動詞和主語保持一致.但是,如果陳述句為“I (don't) think,believe,suppose,figure,assume,imagine,expect,feel等+賓語從句”,反義疑問句的謂語動詞和主語應該同賓語從句的謂語動詞和主語保持一致,如果主句是否定式,反義疑問句要用肯定,反之亦然.請比較如下例句：
I think you will come to the meeting,won't you?(反義疑問句的主語和謂語同賓語從句的主語和謂語一致,因為主句是“第一人稱單數(shù)I+(don't)think等動詞”)
Mary thinks you will come to the meeting,doesn't she?（主句的主語不是第一人稱時,反義疑問句的主語和謂語要同主句的主語和謂語一致）
祝英語學習成功.