D his employers doctor persuaded him to
34. On the safety issue of mobile phones, the manufacturing companies
A hold that the amount of radiation is too small to worry about
B deny the existence of mobile phone radiation
C develop new technology to reduce mobile phone radiation
D try to prove that mobile phones are not harmful to health
35 The writers purpose of writing this article is to advise people
A to buy mobile phones
B to use mobile phones less often
C to update regular phones
D to stop using mobile phones
第二篇 Immune Functions
The immune system is equal in complexity to the combined intricacies of the brain and nervous system. The success of the immune system in defending the body relies on a dynamic regulatory communication network consulting of millions and millions of cells. Organized into sets and subsets, these cells pass information back and forth like clouds of bees flying around a hive(蜂巢). The result is a sensitive system of checks and balances that produces an immune response that is prompt, appropriate, effective, and self-omitting.
At the heart of the immune system is the ability to distinguish between self and nonself. When immune defenders encounter cells or organisms carrying foreign of nonself molecules, the immune troops move quickly to eliminate the intruders (入侵者). Virtually every body cell carries distinctive molecules that identify it as self. The bodys immune defenses do not normally attack tissues that carry a self-marker. Rather, immune cells and other body cells coexist peaceably in a state known as self-tolerance. When a normally functioning immune system attacks a nonself molecule, the system has the ability to remember the specifics of the foreign body. Upon subsequent encounters with the same species of molecules, the immune system reacts accordingly. With the possible exception of antibodies(抗体)passed during lactation(授乳期), this so called immune system memory is not inherited. Despite the occurrence of a virus in your family, your immune system must learn from experience with the many millions of distinctive nonself molecules in the sea of microbes (微生物) in which we live, learning necessitates producing the appropriate molecules and cells to match up with and counteract each nonself invader.
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