A．cured　　　　　　　　　　　 B．released

　　C．caused D．monitored

　　3．The feel­good chemicals produced can help with regular headaches because ________.

　　A．it eases the stress

　　B．it breaks a sweat

　　C．it prevents migraines

　　D．it blocks your pain sensors

　　4．What would be the best title?

　　A．A Cure for Headaches

　　B．Side Effects of Migraine

　　C．The Causes of Headaches

　　D．Advantages of Cardio Workouts

　　【语篇导读】　科学家研究发现有氧运动可以有效治疗偏头痛。

　　1．解析：选C。推理判断题。根据文章最后一段可知，规律的有氧运动或许可以治愈偏头痛，故C项正确。根据文章第十段可知A项表述不正确；根据文章第四段可知，topamirate有副作用，故B项不正确；根据文章第九段中cardio won't be the solution for everyone可知，D项不正确。

　　2．解析：选C。词义猜测题。画线词所在的第七段讲的是流汗会缓解压力，头痛通常由压力引起，如果消除压力，疼痛就会缓解。由此可知trigger意为"引发，激发(尤指一系列事件)"，与cause意义相近。

　　3．解析：选D。细节理解题。根据文章第八段The feel­good chemicals produced when you exercise actually block your pain sensors，acting as a natural painkiller.可知，人类运动的时候，产生令人感觉好的化学物质，能够阻挡疼痛传感器，像一种天然的止痛药一样起作用。

　　4．解析：选A。主旨大意题。通读全文可知，文章主要介绍了有氧运动或许可能治愈偏头痛，因此A项作为文章标题最适合。B项在文章中没有被提及；C、D两项在文章中略有提及，但并非主题。

　　B

　　Do you suffer from cybersickness?

　　The rise of mobile phones has been blamed for a number of social ills, but your smart phone may also be making you physically sick as well. Scientists have identified a condition called "cybersickness"， which they say is the digital version of motion sickness.The phenomenon, which affects up to 80 percent of the population who own smart phones or tablets, leads to feelings of sickness and unsteadiness. It is caused by seeing fast motion on a screen, which covers anything from a car chase in a film to scrolling through web pages on your phone.

The more realistic the visual content appears to you, the higher your chances of getting