第一段：

 1. Professor Colin Blakemore works at Oxford University Medical School doing research into eye problems and believes that animal research has given humans many benefits:

   Doing research into eye problems 是现在分词短语，作伴随状语；research后面常与into搭配。

第二段：

1.there are those who think the tests are simply unnecessary.

2.the international association against painful experiments on animals in an organization that promotes the use oof alternative methods of research which do not make animals suffer.3. Their spokesman Colin Smith says:

 the international association against painful experiments 是一组织名称，译为"反对用动物进行痛苦实验国际协会"；介词on与前面的experiment搭配；which引导定语从句，修饰alternative methods；句末suffer是动词原形，因为前面有make。

3. Their spokesman Colin Smith says:

第四段：
1. Animals research is irrelevant to our health and it can often produce misleading results.
be relevant to / be irrelevant to意为"与…相干 / 与…不相干"。
2. People and animals are different in their reactions to drugs and in the way their bodies work.
reaction 与to搭配，类似的有react to, respond to, response to等搭配；their bodies work是定语从句，修饰the way，关系副词that被省略。
3. We only have to look at some of the medical mistakes to see this is so.

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第一段：
1. But Professor Blackmore stresses:
第二段：
1. It would be completely irresponsible and unethical to use drugs on people that had not been thoroughly tested on animals.
test on在…身上做试验
2. The famous example of thalidomide is a case for more animal testing, not less.
not less后面省略了animal testing。
3. The birth defects that the drug produced were a result of inadequate testing.
that the drug produced是定语从句，修饰defects。
4. If thalidomide were invented today, it would never be released for human use because new tests on pregnant animals would reveal the dangers.
该句是非真实条件句，使用了虚拟语气，表示与现在事实相反。