2016-2017学年 人教版 必修三 Unit 4 Astronomy :the science of the stars language points课件 (5)
2016-2017学年 人教版 必修三  Unit 4 Astronomy :the science of the stars  language points课件 (5)第3页

1. What it was to become was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe. 随后它会变成什么没人知道,知道38-45亿年前这团尘埃才慢慢地形成一个固体的球状体。

1) 句中“What it was to become ” 是一个主语从句,在句中充当主语,谓语动词用单数。 2) was to become: be to do :注定要,必定会