16.【2020•湖北省黄石市】He spent two hours ________ his mother with housework last Sunday.
A．helping B．helped C．to help D．help
【答案】A
【解析】句意：上星期天他花了两个小时时间帮妈妈做家务。
考查非谓语动词。A. helping动名词或现在分词；B. helped过去式；C. to help动词不定式；D. help动词原形。根据英语表达习惯，spend time (in) doing sth.为固定搭配，意为“花费时间做某事”，故help应用动名词形式，故选A。