题目

The first thing ________ my brother is going to do this afternoon is to write a letter.A. why B. who C. that D. whose  答案：【答案】C【解析】试题分析：句意：今天下午我哥哥将要做的第一件事是写一封信。先行词thing有序数词the first修饰，故此处用代词that引导定于从句。故选C。某动物精子细胞核中DNA含量为m，则它的初级精母细胞核中DNA含量为 A.m             B.2m       C.多余2m       D.4m