题目

Tom stood there, ____ what he could do for the poor old man sitting beside him. A.    wondered       B. wondering      C. to wonder        D. having wondered 答案： B 解析: 考查区分谓语动词与非谓语动词的能力。并列谓语用谓语动词；对谓语动词进行修饰，用非谓语动词。wonder伴随谓语动词stood，因此wonder用分词形式作状语，

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