2．Most teens have sleep problems because ________.

　　A．they are more active than children and adults

　　B．school work takes up most of their time

　　C．their hormone levels are higher later at night

　　D．they probably like staying up for no reason

　　答案与解析：C　细节理解题。由文章第二段中的内容可知：大多数青少年有睡眠方面的问题是由于他们体内促进睡眠的荷尔蒙含量到深夜才升高。

　　3．Which of the following is TRUE according to the passage?

　　A．There are many conflicts between students and teachers.

　　B．Some of the teachers have practice and earlier plans.

　　C．Most students are able to do sports and homework before 9：00.

　　D. Ways to solve students' sleep problem vary from area to area.

　　答案与解析：D　细节理解题。根据第三段最后一句可得知，解决青少年睡眠不足的问题采取的措施因地区而不同。

　　4．The passage mainly develops by ________.

　　A．giving reasons B．showing examples

　　C．comparing facts D．offering solutions

　　答案与解析：A　推理判断题。由文章内容可知，这篇文章首先提出观点，然后阐述各个方面的原因，写作方法应是A项。

　　B

　　I travel a lot, and I find out different "styles" of directions every time I ask "How can I get to the post office"．

　　Foreign tourists are often confused in Japan because most streets there don't have names. In Japan, people use landmarks (地标) in their directions instead of street names. For example, the Japanese will say to travelers, "Go straight down to the corner. Turn left at the big hotel and go past a fruit market. The post office is across from the bus stop."

In the countryside of the American Midwest, there are not usually many