Negative: They did not go to Nha Trang last month. Interrogative: Did they go to Nha Trang last month?

Negative: Lan did not see you in the park last week. Interrogative: Did Lan see you in the park last week?

Negative: We were not in the countryside last summer. Interrogative: Were we in the countryside last summer?

Negative: He was not in our class two hours ago. Interrogative: Was he in our class two hours ago?

Negative: Peter did not send that letter to Marry yesterday morning. Interrogative: Did Peter send that letter to Marry yesterday morning?

Negative: Jane's mother did not buy a new car last month. Interrogative: Did Jane's mother buy a new car last month?

Negative: They did not leave for Hai Phong in 1999. Interrogative: Did they leave for Hai Phong in 1999?

Negative: They did not build a new school in my village ten months ago. Interrogative: Did they build a new school in my village ten months ago?