That method of forming causative verbs is no longer productive in the modern Germanic languages, but many relics remain. For example, the original strong verb "fall fell fallen" has a related weak verb "fell felled felled", which means "to cause (a tree) to fall"; strong "sit sat sat" and "lie lay lain" are matched with weak "set set set" and "lay laid laid", meaning "to cause something to sit" or "lie" respectively. In some cases, phonological or semantic developments make the pairs difficult to recognise. For example, "rear" is the regular phonological development of Proto-Germanic "*raizijaną" given in the above list, but the connection between "rise" and "rear" is no longer obvious. (One might guess that the counterpart of "rise" would be "raise", but "raise" is a borrowing from Old Norse, "*raizijaną" continues regularly.) As another example, "drench" was originally the causative of "drink", but the modern meaning of "drench" ("to cause to get wet") is no longer similar to "cause to drink". Similarly, German strong "leiden litt gelitten" ("to suffer") has the derived weak verb "leiten" ("to lead"), which makes sense when one realises that "leiden" originally meant "walk, go" and came to its present meaning through the idea of "undergoing" suffering.