HELP!请教语法题(困惑中...)

cis31UID: 2134397

1.Gold or (silver) bullions serve (into) commerce as mediums of exchange (all) over (the world). KEY:B
2.(Slow) growth in the (early) 1900's,linked with rising unemployment,less (spend),and meager business investments,led many experts (to declare) a recession.KEY:C
3.(Through) the process of imprinting,(the young) of a species rapidly learn to recognize and follow (other members) (of own) species.KEY: D
4.The invention of (fresh) metaphors (today) continues to (make it possible) the vivid (expression) of emotions.KEY:C
5.Henry David Thoreu was (an) Amerian writer who (is) remembered (fo)r his faith in the religious significance of (the nature).KEY: D
帮忙看一下这5道题,具体解释一下,谢谢大家啦~

freshman_cUID: 2148868

into 错了,好象只有in,as.
spend动词
their own
make possible sth/make sth possible
nature 没有the

cis31UID: 2134397

我查了一下,spend也可以做名词啊,这是怎么回事?
还有两道题,帮忙看看吧.
1.The Aeneid was the (greatest) achievement in the golden age of Latin literature, and it (does) continued to (influence) poets through (the) centuries. KEY: B
2.  The oriental fruit fly causes (extensive) damage to grapefruit, lemons, and oranges but does (not) harm to the trees on (which) the fruit (grows). KEY: B

九天玄鸡UID: 193245

第一题是不是应该改成 did?
第二题 not -> no : do no harm to