试题题干
Directions: 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
本题主要考查ai的发音。
captain：[ˈkæptɪn]，sustain：[səˈsteɪn]，contain：[kənˈteɪn]，retain：[rɪˈteɪn]。
A选项中ai的发音为/ɪ/，B、C、D选项中ai的发音为/eɪ/，故本题选A。