Last year, doctors studying the SARS virus were at first confused to find that the virus bound to a receptor in the renin-angiotensin system, a pathway not previously associated with the lungs.

• 去年，研究SARS病毒的医生发现该病毒与肾素血管紧张素系统的受体结合，他们起初感到不解，这是一条先前未与肺有关的途径。