B．She preferred to travel alone.

　　C．She wanted to save some money.

　　D．She hoped to reach the destination earlier.

　　【解析】　细节理解题。根据第二段中的"But I was on a budget"可知，作者预算有限，想节省钱。故选C。

　　【答案】　C

　　2．What can we learn about Piedra Herrada?

　　A．It is at a high altitude.

　　B．It is far from Valle de Bravo.

　　C．It is full of wild animals.

　　D．It is only accessible by riding a horse.

　　【解析】　推理判断题。根据第四段中的"and there is some hiking in thin air, so you must be patient, drink a lot of water, and be in reasonably good shape"可知，在该地攀登时需要在空气稀薄的地方进行一段徒步旅行，旅行者需要有耐心，多喝水，身体还要不错。由此可以推断出Piedra Herrada是在高海拔处。

　　【答案】　A

　　3．What made the author's hiking worthwhile?

　　A．Becoming healthier.

　　B．Breathing in fresh air.

　　C．Finding trees of different shapes.

　　D．Seeing the butterfly migration.

　　【解析】　推理判断题。根据第五至六段的描述可知，虽然作者到达目的地前经历了一段艰辛的徒步旅行，但最后看到美丽的蝴蝶的那一刻，作者感到辛苦是值得的，故选D。

　　【答案】　D

　　4．What type of writing is the text?

A. A news report.　　B. A scientific paper.