【题目】The book was written ______ careful observations and detailed studies.
A. on behalf of B. regardless of
C. on the basis of D. in relation of
在线课程【答案】C
【解析】
试题分析：A. on behalf of代表；B. regardless of不管，不顾；C. on the basis of根据，基于；D. in relation of关系。句意：这本书是基于认真的观察和详细的研究写成的。根据句意选C.