B

　　Organic food is very safe and healthy not just for our

　　 body but also the environment.It is free from harmful chemicals that may affect us.It also strengthens our immune system (免疫系统)．There are a lot of reasons why organic food is much more expensive than conventional food.Growing organic food takes a lot of effort and money and shops selling organic food are using the popularity of organic food to sell it at a much higher price.

　　The number of organic crops is smaller than that of conventional crops.The production costs are very high in organic farming.Many farmers don't use herbicides or pesticides so they have to get rid of the weeds and pests in the fields all by hand, which adds to the cost of organic food.

　　Also, conventional agriculture is heavily supported by the government in terms of taxes, while organic farming gets no help from the government at all.What's more, the farmers can't use sewage sludge (下水道污泥) and chemical fertilizers, which are cheap to buy.

　　Another reason is that the demand is much higher than the supply.While there are many people who are trying organic food, there are only a limited number of farmers who produce it.The output of organic food is low while the transport and packaging costs are the same, which lead to its higher price.

　　Organic farming requires a lot of things that are not needed in conventional farming.But if the demand becomes high enough, the government might one day help organic farming to lessen the costs.

　　语篇解读：有机食品organic food也叫生态或生物食品，是国际上对无污染天然食品比较统一的提法。吃有机食品对人们有很多好处，而有机食品也变得越来越流行。

　　5．Which of the following is the closest in meaning to the underlined word "conventional" in Paragraph 1?

　　A．Simple. B．Real.

　　C．Usual. D．Similar.

　　解析：选C　词义猜测题。根据第一段"There are a lot of reasons why organic food is much more expensive than conventional food." 可知，organic food和conventional food是两种不同的食物，有机食物organic food相对于传统食物conventional food比较新，故conventional的意思是usual的意思。

　　6．All the following are the reasons why organic food is more expensive EXCEPT that________.

　　A．its production is limited

B．its transport and packaging costs are higher