试题题干
In each of the following groups of words, there are four underlined letters or letter combinations marked A, B. C and D. Compare the underlined parts and identify the one that is different from the others in pronunciation.
参考答案
正确答案：
试题解析
本题考查划线部分的发音。
collision：[kəˈlɪʒn]；pension：[ˈpenʃn]；dimension：[daɪˈmenʃn]；extension：[ɪkˈstenʃn]。故A选项collision中的sion发音与其他三个不同。