如题，粗体的一句话，我的理解是“褶皱通常呈狭长的一组一组出现。”
For a plunging fold, the hinge is always plunging to the younger end of the fold. If the fold is a syncline, the hinge plunges to the open side (younger side); and if the fold is a anticline, the hinge plunges to the close end (still younger end, Figure 13). (倾伏褶皱的枢纽总是向相对新的地层一端倾伏)
Using the principle provided above, geologists typically work from available surface outcrops of rock formation to reconstruct subsurface structures. In fact, folds are typically found in elongated groups. A strip of country in which the rock layers are folded-that is, a fold belt (褶皱带)-suggests that the region was compressed at one time by horizontal tectonic forces.
