This study aims at arousing college students' metacognition in detecting lexical cohesion during online text construction as WordNet served as a lexical resource. A total of 83 students were requested to construct texts through sequences of actions identified as interaction chains in this study. Interaction chains are grouped and categorized as a meaningful entity in order to investigate the students' thinking process and behavior in general and to understand the interaction between the computer and the students in particular. From the interaction chains, it was found that some students revised incorrect sentences to correct ones. In making correct revision, they needed to assess incoming information, interpret and organize textual information, engage in thinking what they know, monitor their own meaning construction process, and take remedial actions to reach comprehension. The rate of correct sentence selection increased from 34.04% to 55.02% in three sequential text construction tasks. The recognition of lexical cohesion was found to be a determining factor for successful construction of a text. (Contains 10 tables and 9 figures.)