1、Critics also argue that commercial genetic testing is only as good as the reference collections to which a sample is compared.
重点分析下 to which a sample is compared
2、This means that a DNA datebase may have a lot of date from some regions and not others,so a person`s test results may differ depending on the company that processens the results.
第一句话，critics是主语argue是谓语，that后面是宾语从句，然后to which 引导的是修饰collections的定语从句，因为compare的固定用法是compare to/with sth, 在which引导从句时候compare后面的to提到了which前面。评论家也指出商业的基因检测仅仅和类似作为样本的参考搜集一样。第二句话，this是主语，means是谓语，that后又是宾语从句，so后面是结果状语从句，在这个结果从句里test results是主语may differ是谓语，depending on the company that ...是条件状语，that processes the results是修饰comp
这篇文章本人读过。第一句一楼错了！！批评家还争论：商业性质的基因测试就仅仅和用来进行样本比对的参数集差不多。较复杂定语从句的指代关系你可以这样来看 ，比如 to which a sample is compared----还原过后----a sample is compared to which,显然这里的which 指代的是referenc
