1. Beneath his gruff exterior he´s really very kind-hearted.
    他外表粗鲁, 心地却十分善良.

2. The seed has a hard exterior covering.
    这个种子的外壳很硬。

3. On the exterior, he was cool, calm and collected but on the interior, stress was killing him.
    表面上，他显得沉着、冷静和泰然自若，但他内心深处的压力使他筋疲力尽。