1)built-in;inner,inside,interior; internal; in-house,内部的2)internal,intrinsical,内（部）的3)division of labour in society,社会内部的分工4)light gradients across leaf section,叶片内部的光梯度5)Light distribution within leaf,叶片内部的光分布6)physical parameters of the earth's interior,地球内部的物理参数
