Going on field trips:
1) Opinion: better understand the concept in studies.
    Example: observe the migration of ants.
    分析：students can directly observe the path and the characteristics of the ants migration. while it is difficult to understand such hard concept through literal learning.
    
2) opinion: Improving passion of study.
    Example: students enjoy going to museum.
    分析：students do not like reading solitarily. Teenagers always prefer to watch real artifacts.

3) opinion: Improving health condition.
    Example: taking exercise in the fields.
    分析： Students are juveniles. They require a open environment for growing up healthily. Always sitting at room is harmful for their health.


Study at classroom:
1) opinion: greater efficiency of study.
    Example: professor's lecture
    分析：giving a lesson through a lecture in a fixed classroom only takes about an hour. What's more, a series of subjects can be given in one day. But one field trip usually represents one subject. And it always takes a day long to finish it.

2) opinion: quieter
    Example: classrooms are located inside school
    分析：students can learn better in a quiet environment. while outter environment is always noisy and complex, making students fluttered and unfocus.

3)opinion: More books to read, improving the ability of self-study.
   example: library
   分析： students could go straightly to the library in school. While students have less chances to visit public library at field trips. What's more, teachers give guidance and knowledge directly to students at field trips. While students need to find resources of particular subject on their own.