问题补充：
The economist claimed that the crisis and the suffering caused had a great influence on the whole world.
A. it
B. which
C. what
D. they
答案：
(答案→)A. it
B. which
C. what
D. they
解析：考查代词：句意：经济学家宣称经济危机和它造成的伤害对整个世界都有很大的影响。it指代的the financial crisis 是定语从句 it has caused 的 主语。定语从句省略了which/that，从句的意思是 it(the financial crisis) caused (the suffering)，cause 是个及物动词，wihch/that 在从句中是宾语，指代the suffering。 如果只用which/that，而不用it的话，从句的主语就没了。讲不通了。所以，如果只填一个词，就只能把连接词省略，而不是从句的主语省略。选A。
