41. DIT has since built a rich tradition of theoretical models over the past two decades. 42. Monitoring is another important concept in some theoretical models of learner use of L2 knowledge. 43. In most cases, their theoretical models can adapt to negative population growth as easily as positive. 44. A number of theoretical models have been developed to explain how certain groups change over time. 45. Maddi ( 2006 ) developed a theoretical model of hardiness as a tool for developing resilience. 46. There are competing theoretical models for vacuum, however. 47. All of these features of the velocity field also appear in theoretical models for lifting flows. 48. Astronomy theorists endeavor to create theoretical models and figure out the observational consequences of those models. 49. What scientists do is reason from the available evidence to a theoretical model that explains it. 50. The result is a theoretical model of intelligence.
