The study, published in Nature Communications on May 13, showed that blood plasma levels of angiotensin Ⅱ are higher in H7N9 patients and could be used to predict their physical worsening.

　　Angiotensin Ⅱ is a human protein contained in plasma, the vascular (血管的) wall, heart and kidney to regulate blood pressure. It is closely linked to serious lung injury. H7N9 patients with higher levels of angiotensin Ⅱ carry more viral load (病毒载量), said Li Lanjuan, researcher at the Chinese Academy of Engineering and a specialist in H7N9 prevention. "It is particularly obvious in the second week of human infection. The angiotensin Ⅱ level of patients in critical condition keeps going up, while that of mild cases tends to drop，" Li said.

　　Li added the new finding could help in clinical practice. Medical personnel could adopt more effective and reliable treatment measures for patients suffering different conditions. "This study will provide a new perspective to H7N9 pathology (病理) and potential treatment for future cases，" said Ed Gerstner, executive editor of Nature Communications.

　　The study was led by researchers of the First Affiliated Hospital of Zhejiang University, Chinese Academy of Medical Sciences and Chinese Center for Disease Control and Prevention. They collected plasma from 47 H7N9 patients in cities of Hangzhou, Shanghai and Nanjing and analyzed the connection between angiotensin Ⅱ and viral load.

　　H7N9 was first reported in China in March 2013. The virus causes severe disease in humans, including acute and often fatal breathing failure.

　　语篇解读：本文是说明文。文章讲的是中国科学家发现了一种人体血浆蛋白与H7N9病死率有关。

　　1．What does the passage mainly talk about?

　　A．Chinese scientists found a human blood protein associated with the H7N9 death rate.

　　B．Chinese scientists have made a new medical discovery.

　　C．A new perspective to H7N9 pathology provided by a medical study.

　　D．A report of H7N9 death rate.

　　解析：选A　主旨大意题。纵观全文可知本文讲的是中国科学家发现了一种人体血浆蛋白与H7N9病死率有关，故选A。

　　2．The underlined word "critical" in the third paragraph most likely means ________.

　　A．unimportant　　　　　 　B．mistaken

　　C．urgent D．successful

　　解析：选C　词义猜测题。根据第三段最后一句话中的"in critical condition keeps going up, while that of mild cases tends to drop"可知critical condition与mild cases进行对比，故critical与mild意思应该相反，表示"危急的"，故选C。

3．According to the passage, which of the following statements is NOT true?