问题
选择题
It is thought that one billion people in the world,_____ is half the world’s workers, earn their living by farming.
A．if
B．that
C．which
D．what
答案
答案：B
句中“half the world’s workers”是对“one billion people in the world”的补充说明。“that is”是“that is to say”的省略说法
【标签】插入语和定语从句