...
The "Currently Reading" tab gives users the option of fetching new sentences for the current study focus vocab (highlighted in blue both in the study focus category and in the current sentences). The yellow highlight greatly increases the locus of attention to certain warnings or instructions under the "fetch next sentence" button. Note that each sentence block is separated by alternating blue/white colors and the "Close" button for each sentence block. Clicking on the "Close" button will move the corresponding sentence block to the "Closed Sentences" tab, in a stack-like fashion (chose for better feedback).
The "Closed Sentences" tab serves almost like a recycling bin. Creating a place for users to dispose and restore sentence blocks. Additionally, to improve efficiency in terms of scalability, a search option is added to allow users to filter through closed sentences, by either PinYin, English, or Chinese. The reason a "Closed Sentences" tab was implemented, as explained above, is due to overwhelming reader request for efficiency and navigation. Although this increases the complexity of the design, it offers better visibility and user control since it allows the user to "clean up" the "Currently Reading" list of sentences.
Sentence Contribution 
The Sentence Contribution tab allows the user to enter a sentence, and once submitted, the contributed sentence can be viewed below (and deleted). The reason we have contributed sentences displayed below is that during our paper prototyping, where contributing a sentence was simply modal popup dialog, the users were unsure where the sentence they had contributed had gone, or how they could delete it from the database if they had accidentally typed the wrong thing. Notice how in all the sentence blocks, the study focus word is highlighted in blue, the "checked" vocabs (see Vocabulary Search) are displayed in red, and non-selected words are in grey.
Implementation
Our user interface runs in-browser using Silverlight, and is implemented using C#. It uses Silverlight's layout system to organize the widgets, and is therefore resizable.
...