Question

【题目】 people watched Shenzhou Ⅸ spacecraft into space successfully in the world.

A. Billion B. Billions

C. Billion of D. Billions of

Answer 1

【答案】D

【解析】句意：世界上数十亿人观看了神舟飞船成功进入太空。billion名词，十亿；固定搭配billions of，意为“数十亿”，表示约数。故选：D。