Teacher:In this task, you will be presented with a context from an academic paper and a question separated with a 
. You have to answer the question based on the context.
Teacher: Now, understand the problem? Solve this instance: To account for sequences of words and characters that might carry useful information, we extracted word unigrams, bigrams, and trigrams as features. 
 Question: Which features do they use to model Twitter messages?
Student:
word unigrams, bigrams, and trigrams