The researchers say that television viewing may be a risk factor for all Alzheimer's disease, but more researches needed to establish a link.

研究人员表示，电视可能是所有阿尔茨海默症的危险因素，但是仍需要更多的研究来建立联系。

It has a fossil on display that some scientists call the most important fossil of all time because it establishes a link between birds and dinosaurs.

它展出了一块被一些科学家称为有史以来最重要的化石，因为它证明鸟类和恐龙之间存在某种联系。

While most of the evidence supported the hypothesis that red meat could also cause cancer, there were too many well-designed studies that couldn’t establish a link.

虽然大多数证据都支持红肉也可能致癌的假设，但有太多精心设计的研究无法建立联系。