SummarizationRead each of the following short paragraphs and complete the phrase or sentence that expresses the main idea of the paragraph. The first letter of the missing word is given be fore the blank.Para.5All those who have set foot in Antarctica agree that its main and most cruel characteristic is wind. When we wintered in Adelie Land the wind on 5 July blew nonstop for eight hours at an average speed of 170 mph; gusts were recorded of over 150 mph, and the average wind speed for the month was 63.3.In these conditions it was impossible to stand for more than a few seconds.5.The biggest p______to life in Antarctica is wind.
【正确答案】：problem
【题目解析】：P63
