giải dùm tui bài này vs mn

6. According ___________tradition, women wear ao dai on special occasions. *
a.by
b.with
c.in
d.to
7. This time yesterday, I _______ the story of Saint Giong. *
a.read
b.was reading
c.am reading
d.has read
8. While the teacher was teaching, Mai _______ on her smart phone. *
a.plays
b.played
c.was playing
d.had played
9. The Hung King festival is organized to _________ the contribution of Hung King. *
a.commemorate
b.pay
c.preserve
d.celebrate
10. Many aquatic animals and plants have died________ the oil spill. *
a.because
b.due to
c.as
d.since