问题补充:
-- Did you read a book about customs last week?
-- Yes, I found very useful to know the customs of foreign countries.
A. that
B. this
C. it’s
D. it
答案:
A. that
B. this
C. it’s
(答案→)D. it
解析:句意:上周你读了一本关于风俗的书吗?是的,我发现了解外国的风俗习惯非常有用。Find + 名词 + 形容词,是find的一种习惯用法,其中名词作宾语,形容词作宾补。此句中to know the customs of foreign countries是真实宾语,为了使得句子结构平衡,就将其放在了后面,让it来代替它充当宾语。所以选D。