1 . Chemical fertilizers kill the helpful __________(细菌) and pests as well as the harmful ones.

2 . Until now, it is still unknown to the scientists which _____ (细菌) causes the infection.（根据汉语意思填空）

3 . When you eat the raw vegetables, all of those __________ (细菌) will go into your stomach. （根据汉语意思填空）

4 . That boy is being a real______.

A．insect

B．pest

C．worm

D．bacterium

5 . Each year, tens of thousands of people die because they are infected with antibiotic-resistant _______.

A．balconies

B．bandages

C．bacteria

D．banquets

6 . Eggs, meat, vegetables and other foods can easily be poisoned by microorganisms such as ______.

A．phenomena

B．dilemma

C．diploma

D．bacteria