问题详情:
After a heated discussion, they still don’t know at all _______.
A.what is he working out B.what he is working on
C.what did he work on D.what he is working out
【回答】
B
【详解】
考查动词短语和宾语从句。句意:经过激烈的讨论,他们仍然一点也不知道他在做什么。work on表示“从事于”,work out表示“算出”,分析句子结构可知此处为宾语从句,从句中的working on缺少宾语,故B项正确。
知识点:动词
题型:选择题