center of the Earth的用法和樣例：
例句
- Ketty's wing had hurt before because of the bulrush.They flied very slowly.
凱蒂的翅膀在蘆葦地中受了些傷，所以他們飛得很慢。 - Usually, the cactuses have long roots and they take their roots deep into the earth so that they can absorb the water from deeper soil.
仙人掌的根通常很長(cháng)，它們把長(cháng)長(cháng)的跟扎入地中，這樣它們就可以吸收到更深的泥土中的水分了。
