1.The ratio of the work done by the machine ______ the work done on it is called the efficiency of the machine. A. against B. with C. ToD. for C 【句意】机器的输出功与输入功之比被称为机械效率。 【解析】固定搭配。由固定搭配“the ratio of… to ………与……之比”知C项正确。 2.Like all sciences, psychology developed out of the study of philosophy, ______through the centuries has tried to understand the ultimate nature of the world. A. who B. that C. WhichD. it C 【句意】像所有的科学一样,心理学是由几个世纪以来试图去了解世界终极本质的哲学研究发展而来的。 【解析】语法结构——which引导非限制性定语从句。由空格前逗号“,”的对应知这里属于非限制性定语从句,故可直接排除B项和D项;再由这里先行词“the study of philosophy”指代物知C项“which”正确。 3.The pollution question as well as several other issues is going to be discussed, when the congress is in ______ again next spring. A. assembly B. SessionC. conference D. conventional B 【句意】污染问题以及其他几个问题将于明年春季代表大会再次召开时被讨论。 【解析】名词和形容词词义辨析。由句中关键词“when congress…代表大会……时”的对应知可构成“in session在开会”的B项正确。assembly“装配;集会”;conference“会议”;conventional“遵循习俗的;传统的;依照惯例的”。