Roberta Litt's second-graders at LaFollette Elementary School failed to come up with a single question for visiting local historian Elmer Rasmussen Tuesday. 'Come on, folks,' said Litt, scolding her class. 'Mr. Rasmussen was nice enough to come all the way down here today to tell us about immigrant-farmstead life in the 19th century. I find it hard to believe that not one of you has a question.' Following an uncomfortable two minutes of silence, Litt ordered the children to put their heads down on their desks for the remainder of the period. 