GWD3  Q30:

Which of the following most logically completes the argument?

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

不太明白E 谢谢拉

因为不管食物有没有经过辐射处理，它们都需要cook，所以，proponents的观点是误导的，好象因为辐射造成的b1比cook少，所以辐射无害。。。

但是辐射和cook会加大b1的损失。

for food that is both irradiated and cooked, the reduction of vitamin B1 associated with either process individually is compounded,

这句话如何理解?