Match the words and expressions on the left with the explanations on the right
21.export earnings
22.perishable
23.expertise
24.specific duty
25.tap
26.input 
27.pooling
28.preference
29.protectionism
30.underwriter imports 

a.easily to go bad
b.something that is put in business operation
c.a practical advantage given to one over others
d.a person who carries on insurance as a business
e.duties levied on the basis of quantity,weight,size etc.of the goods
f.a combination of funds formed for common advantage
g.the theory of the system of developing home industries through duties and other means imposed on competitive imports
h.expert skill or knowledge
i.to take what is needed from,to exploit
j.money earned on the sales of goods to other countries