短语讲解：

1. According to NASA, the asteroid has no chance of hitting Earth.

according to 根据，按照；取决于；据…所说
例句：They do everything according to Hoyle.
他们一切都按照规定办理。

2. TX68 is expected to approach the Earth again on September 28, 2017.

be expected to 有望做某事；被期待做某事
例句：I do not know why the ceiling should be expected to have that effect.
我不明白怎么会认为定个上限就会有这种作用。