關於GRE閲讀短文的練習題

編輯點評： 新GRE閲讀考試考察大家的方面較多，除了大家需要擁有一定的詞彙量以外，還需大家在解題的時候能夠迅速瞭解出題者的`意圖，這就需要大家充分發揮自己的邏輯理解能力和推理能力，大家可以利用下文的新GRE閲讀短文練習進行練習。

Certain extremely harmful bacteria found only in sewage are difficult to detect directly. Testing for E. coli, an easily detected and less harmful type of bacteria, in ocean water would be a reliable way of determining whether or not these more harmful bac-teria are present, since ocean water contains E. Coli only if the water is contaminated with sewage that contains the harmful bacteria.

Which of the following, if true, most seriously weakens the argument?

There are many different strains of the E. coli bacteria, and only some of these strains are harmful.

Some types of bacteria found in sewage are neither disease-causing nor difficult to detect directly.

Some of the types of bacteria found in sewage along with E. coli are not harmful to people unless the bacteria are ingested in large quantities.

E. coli dies out much more quickly than some of the more harmful bacteria found in sewage and then can no longer be easily detected.

Some of the types of bacteria found in sewage along with E. coli reproduce at a slower rate than E. coli.