题目

One of the most important questions they had to consider was ____ of public health.   A. what             B. this              C. that                 D. which   答案：C句意: 他们必须考虑的最重要的问题之一就是公众健康问题。此题考查的是that的指代用法, that在此等于the question。新的生命是从何时开始的？ （ ）A．卵细胞和精子  B.受精卵  C.胚胎  D.婴儿出生时