1.Two factors weigh heavily against the effectiveness of scientific research in industry.
weigh against 对……不利，将（某事物）与（其他事物）做对比
例句：At least there are benefits to be weighed against the costs!
和费用相比，至少利润还是有的。
2.One is the general atmosphere of secrecy in which it is carried out, the other the lack of freedom of the inpidual research worker.
in which在用定语从句时，不能破坏原来的句子结构，通常由介词和疑问副词组合在一起构成定语从句。最典型的一句就是新概念第三册，世界上最长的吊桥中的一句：
He described it as "a very agreeable situation located within two small hills in the midst of which flowed a great river."
3.In so far as any inquiry is a secret one, it naturally limits all those engaged in carrying it out from effective contact with their fellow scientists either in other countries or in universities, or even, often enough, in other departments of the same firm.
either…or…意为“或者……或者……；不是……就是……”之意。表示两者之一，连接句子中两个并列的成分。例如：
When the girl is happy, she either sings or dances.
那个女孩高兴时，不是唱就是跳。（此句中either…or…连接两个动词，因为主语是单数第三人称，谓语动词要用其相应的形式。）
either…or…连接两个主语时，其谓语动词应与最近的一个主语在人称和数上保持一致，这就是我们通常说的“就近原则”。例如：
Either you or I am going there tomorrow.
明天要么你去那里，要么我去那里。
注意：如果把上句变成一般疑问句，助动词形式与主语you保持一致，所以要用are提问，而不是am。例如：
Are either you or I going there tomorrow?
明天是你还是我去那里？
