abbr. 数资料发送机(Digital Data Transmitter);开发与技术部(Department of Development and Technology);二氯二苯三氯乙烷(Dichloro-Diphenyl-Tricgloroethane);数带(Digital Debugging Tape);双二极-三极管(Double Diode-Triode)
4.Nonbiodegradable pollutants, such as certain chlorinated hydrocarbon pesticides (e.g.DDT) and heavy metals, such as lead, copper, and zinc in some industrial effluents, accumulate in the environment.