3. Complex infinitive for n. or pron. to do 我们必须详细地研究这种材料的性质。 It is necessary for us to study the properties of this material in detail 阳光到达地球需要大约八分钟的时间 It takes about eight minutes for sunlight to reach the earth 个电路只包含电阻是罕见的。 It is rare for a circuit to contain only resistance.3. Complex infinitive for + n. or pron. + to do 我们必须详细地研究这种材料的性质。 It is necessary for us to study the properties of this material in detail. 阳光到达地球需要大约八分钟的时间 It takes about eight minutes for sunlight to reach the earth. 一个电路只包含电阻是罕见的。 It is rare for a circuit to contain only resistance