一题完成题，想不明白！求解！

Xiaotongdi

The irradiation of food kills bacteria and thus retards spoilage.However, it also lowers the nutritional value of many foods.For example, irradiation destroys a significant percentage of whatever vitamin B1 a food may contain.Proponents of irradiation point out that irradiation is no worse in this respect than cooking.However, this fact is either beside the point, since much irradiated food is eaten raw, or else misleading, since _______.

1. many of the proponents of irradiation are food distributors who gain from food’s having a longer shelf life
   
2. it is clear that killing bacteria that may be present on food is not the only effect that irradiation has
   
3. cooking is usually the final step in preparing food for consumption, whereas irradiation serves to ensure a longer shelf life for perishable foods
   
4. certain kinds of cooking are, in fact, even more destructive of vitamin B1 than carefully controlled irradiation is
   
5. for food that is both irradiated and cooked, the reduction of vitamin B1 associated with either process individually is compounded
   

答案是E。我分析了很久还是看不明白。

sdcar2010

99  There are two voices here.  One is the proponents of irradiation.  The other is the author.  The author says "However, this fact (that irradiation is no worse than cooking in terms of destroying vitamin B1) is either beside the point or else misleading."

It is misleading because if you want to cook the food in the end, irradiating the food before cooking would destroy more vitamin B1 than not irradiating the food, especially when E is right.

Irradiation alone destroys X grams of vitamin B.
Cooking alone destroys Y grams of vitamin B.
When irradiation and cooking are combined, the combined effect would destroy (X + Y) gram of vitamin B, more than the share destroyed by cooking only. In the argument, the assumption is that irradiation ONLY destroys the portion of vitamin B which would be eventually destroyed by cooking.

Misleading!!!