Task: Question Answering
Input (English): passage: Lake Tahoe never freezes. Since 1970, it has mixed to a depth of at least 1,300 ft (400 m) a total of 6 or 7 times. Dissolved oxygen is relatively high from top to bottom. Analysis of the temperature records in Lake Tahoe has shown that the lake warmed (between 1969 and 2002) at an average rate of 0.015 °C per year. The warming is caused primarily by increasing air temperatures, and secondarily by increasing downward long-wave radiation. The warming trend is reducing the frequency of deep mixing in the lake, and may have important effects on water clarity and nutrient cycling.
 question: does lake tahoe freeze over in the winter?
Output (English): No