A.用Hg²⁺鹽直接滴定

B.用AgNO₃直接滴定

C.用AgNO₃沉淀后，返滴定

D.用Pb²⁺鹽沉淀后，返滴定

A．AgNO3，Na Cl

B．AgNO3，AgNO3

C．AgNO3，KSCN

D．AgNO3，NH4SCN

A．莫爾法測定 Cl-

B．佛爾哈德法測定 Cl-

C．法揚司法測定 Cl-

D．莫爾法測定 Br-

A．硫酸根電極

B．鐵電極

C．玻璃電極

D．鉑電極

B、while

C、than

D、then

The biggest misconception held by many organic lovers is that organic produce is not grown with fertilizers (肥料) or pesticides (殺蟲劑). That’s simply wrong. Organic fertilizers and pesticides are manufactured by all the major producers. Pests attack crops whether they’re certified organic or not; and all plants take nutrients (營養物) out of the soil that have to be replaced.

Many think organic farms handle that through soil management. And so they do, but so do all farms. Every farm rotates crops as much as possible to keep the soil healthy and reduce the spread of pest; by no means is this unique to organics. It’s been a farming fundamental for centuries.

Chemicals are one of a farm’s biggest expenses, and both organic and conventional farms strive to reduce that expense. Modern agriculture depends on efficient fertilizers that deliver the needed nutr

1What is a traditional method used to keep the soil healthy?

A、Avoiding too much use of chemicals.

B、Replacing soil nutrients with fertilizers.

C、Using the soil for organic produce only.

D、Rotating crops as much as possible.

2What is one characteristic of organic practices?

A、They use no fertilizers or pesticides.

B、They use more efficient fertilizers.

C、They ban the use of new seed strains.

D、They adopt the latest farming techniques.

3From Paragraph 6 (the paragraph beginning with “at the end of the day, …”), we can infer that ______________.

A、organic food is no different from conventional produce

B、the quality of organic produce can be highly unstable

C、the results of the tests in the videos are not fair enough

D、volunteers participating in these tests are not qualified

4At the end of the passage, the writer tends to suggest that _____________.

A、the benefits of organic food are overstated by marketing

B、organic practice involves no scientific knowledge at all

C、people should be practical and consume less organic food

D、it is easy for people to be fooled by bad science today

5What is the main purpose of the passage?

A、To compare organic food with conventional produce.

B、To correct people’s wrong beliefs about organic food.

C、To explain why organic food is so popular with people.

D、To convince that conventional produce is better for health.