Question

【題目】The teacher spent a long time _____ the problem to the boys after class. (解釋)

Answer 1

【答案】explaining

【解析】

句意：下課后，老師花費了很長時間向孩子們解釋了這道難題。
解釋：explain。spend...(in) doing sth. 花費……做某事。此處動名詞作賓語，介詞in可省略。故答案為explaining。