词汇	ecdem-
释义	ecdem-stem.离家away from home相关词根ecdemo-
随便看	observational studies observational study Observational Study and Intermingling Factors observational survey observational synthesis observational technique observational techniques in space astronomy observational terms observational-theoretical distinction observational tools observational trajectory observational twilight observational unit observational variance Observation Amphibian Plane observation analysis Observation and aiming instrument observation and analysis observation and analysis system observation and assessment observation and communication observation and communic-ation station observation and examination observation and imitation of character observation and learning activities