绩效概念的界定需要把握权变的原则和（）。

基础训练篇（5）

It is known to all (1)___________ the Chinese diet is considered to be the (2)__________(healthy) in the world because it (3)__________ (contain) a lot of fruit and green vegetables. It is rich (4)___________ fiber and low in sugar and fat.

How (5)_____________ the Western food? It has too much fat in the form (6)______________ potato chips, chocolate and so on.  It is also rich in sugar in the form of cakes, soft drinks, etc. As (7)______ _ result, the (8)________________(west) usually become very fat and have bad (9)____________ (tooth), and many of them even die at an early age from heart (10)______________ (ill).