1.She lived in the mountain village ___the years 1940-1950.
a.between b.during c.in d.since
2.The American Civill War lasted four years before the north won ____the end.
a.by b.at c.in d.on
3.May had finished her homework ____the time I got home.
a.until b.by c.at d.when
4.We stayed at the lab ____our teacher returned.
a.till b.by c.during d.while
5.Don't worry.He will return ____.
a.before long b.long before c.long long ago d.long ago