1.d.period
in the period of construction施工期间
2.c.stare
stare at盯着
3.b.with
带着
4.d.that
that是代词.代替前面提到的the population
5 d.concerning
.found sb doing sth 看到某人正在做某事
6d.affected影响
7arousing引起
8d.speaking
avoid doing sth 避免做某事,固定搭配
9a.had interrupted
因为“It was the +序数词+time +从句”从句中动词用过去完成时；“It is the +序数词+ time +从句”从句中的动词用现在完成时.
10c.by
11A.abolish 废除,取消
12 a.when
13c.were destroyed
14 c.what
15b.much
16 c.amazed
17b.aware
18 c.information
19c.challenged
20 a.obey