比如，下面的两段，是摘选于Nunan的how to teach Young learners一书中，我将段落大义写在后面：
Starting age affects the rate of learning. Where grammar and vocabulary are concerned, adolescent learners do better than either children or adults, when the length of exposure is held constant. W西宁卵子库here pronunciation is concerned, there is no appreciable difference.
Both number of years of exposure and starting age affect the level of success. The number of years of exposure contributes greatly to the overall municative fluency of the learners, but starting age determines the levels of accuracy achieved, particularly in pronunciation. (Ellis, 壹玖捌伍, p. 壹零陆)