accessible surface

基本解释

An ideal den must be deep underground, where the earth is warm, but accessible from the surface via burrows or natural fissures.
理想的巢穴必须深入土壤很温暖的地下，但可以通过地洞或自然裂缝从地面进入。
By volume, only 3 percent of all water on earth is fresh water, and only about 1 percent is easily accessible surface fresh water.
依重量来看，只有3%在地球的水是新鲜水，只有差不多1%是趋近于表面新鲜水。
Clearance: Shortest distance between two conductive parts or between a conductive part and the accessible surface of the toy, measure through air.
两导体之间或导体与玩具可触及表面间最短的空间距离。