Besides free movement of goods and services and adoption of common external trade policy，factors of production such as labor, capital and technology are free to move among members ______ they can be utilized in a more efficient and productive way.
A、so that
B、so far
C、then
D、however
【正确答案】：A
【题目解析】：Besides free movement of goods and services and adoption of common external trade policy，factors of production such as labor, capital and technology are free to move among members so that they can be utilized in a more efficient and productive way.参见教材P36。
