问题
单项选择题
The second half of his voyage was by far the more dangerous part ______ he sailed round the treacherous Cape Horn.
A．where
B．of which
C．during which
D．that
答案
参考答案：C
解析：逗号后的部分是非限定性定语从句，关系副词在从句中做时间状语，during which就相当于during the second half of his voyage，故选C。