"Mussel Watch" has been proven successful as a very applicable approach to monitorthe status and temporal changes in organochlorine pollutants using marine bivalve musselsas sentinel organisms, owing to their sessile lifestyle, wide distribution, high tolerance tocontaminants, and the convenience of sampling.

On the basis of the Multiple Choice test score model that the observed score Z is the sum of true score Y and the guessed score X, this paper discussed the regressive function μ y|z which is the best estimate of Y on Z.

Grammatical study has a dynamic process of full observation,full description and full explanation.