《任務型語言教與學》由於內容選擇精當而受到了外語界的好評，在科研論文中被廣泛引用，對推動我國外語教學和研究的發展起到了重大作用。近年來，隨著研究的不斷擴展和深入，國內學界對研究資料有了新的需求，像“任務型教學法”、“英語作為國際通用語”、“二語習得的跨學科研究”等逐漸成為了熱門的話題。

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Acknowledgements
Preface
1 Tasks in SLA and language pedagogy
2 Tasks，listening comprehension，and SLA
3 Tasks，interaction，and SLA
4 Tasks，production and language acquisition
5 Focused tasks and SLA
6 Sociocultural SLA and tasks
7 Designing task—based language courses
8 The methodology of task—based teaching
9 Task—based assessment
10 Evaluating task—based pedagogy
Glossary
Bibliography
Index

Information gap： one-way vs. two-way tasks
One-way tasks and two-way tasks are required information exchange tasks that are distinguished in terms of whether the information to be shared is split one-way， i.e. held by a single person or between two or more people.The listen-and-do tasks that we considered in Chapter 2 are one-way tasks （with the teacher holding all the information to be communicated）. The same-or-different task in Figure 1.2 in Chapter 1 is an example of a two-way task. In the case of one-way tasks the burden of completing the task successfully is placed on the participant who holds the information，although other participants can contribute by demonstrating when they comprehend and when they do not.s In contrast， in two-way tasks all the participants are obligated to participate in order to complete the task.
Long （1980） compared the interactional adjustments that occurred in NS-NS and NNS-NS dyads on two sets of tasks. The first set consisted of （1） a narrative task， （2） giving instructions， and （3） discussing the supposed purpose of the research. They are all one-way tasks， classified by Long as '- information exchange'. The second set consisted of （4）， a conversation task， and （5） and （6）， communication games. They were all two-way and thus '+ information exchange'. Long found that in the one-way tasks the NSS-NS dyads did not engage in significantly more meaning negotiation than the NS-NS dyads but in the two-way tasks there were significantly more confirmation checks， comprehension checks， and clarification requests in the NNS-NS dyads. In other words， NSs were much more likely to modify their interaction to take account of NNSs' comprehension problems in two-way tasks than in one-way tasks.
A number of studies， however， have failed to show that two-way tasks promote more negotiation than one-way tasks. Gass and Varonis （1985） compared the NNS-NNS interactions resulting from a describe-and-draw task and a jigsaw listening task， which required participants to share information in order to work out who had committed a robbery. They found that more indicators of non-understanding occurred in the one-way task，although the difference was not significant. Jauregi （1990， reported in Ondarra 1997） also found that a one-way task （describe-and-draw） produced more negotiation work than a two-way task that involved talking about future plans.
What conclusions can we reach? Long （1989： 13） feels confident enough of the research results to claim that 'two-way tasks produce more negotiation work and more useful negotiation work than one-way tasks'.However， such a conclusion might be premature given that two studies to date do not bear out this conclusion. Furthermore， no study to date has actually investigated whether any difference in learning results from the use of one-way and two-way tasks. Also， the distinction between one-way and two-way tasks may not be as straightforward as it sounds. Gass and Varonis （1985）， for example， suggest that it is continuous rather than dichotomous. As we will see later， task implementation variables can also impact on the kind of interaction that takes place in one-way tasks， making them more or less interactive.
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