I think the_____invention is a mobile phone. What about Wap版

试题详情及答案解析: I think the_____invention is a mobile phone. What about you?
A、most helpful
B、more helpful
C、helpfulest; 答案：A; 试题分析：句意：我想最有用的发明是手机。你呢？根据句意可知该用最高级，而helpful的最高级是在其前面加most，而不是加后缀-est，所以选A。
考点：考查形容词的最高级。