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
网友回答
A. if
(答案→)B. that
C. which
D. what
解析：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