1.in addition 另外,此外
There is, in addition, one further point to make.
此外,還有一點要說。
2.billions of years 數十億年
Astrogeologists suspect that these scarps having formed billions of years ago as the planet's surface cooled and shrank.
太空地質學家猜測這些陡坡是在幾十億年前當行星表面冷卻收縮時開始形成的。