1. When this sign is repeated it is usually associated with a nominal (noun) meaning (i.e., the sign names an activity) like "locking" (e.g., "Locking all the doors and windows took ages."), or a thing like "a key". However, repetition alone does not make it a noun as it could also still be used as a verb to mean "to turn a key or lock again and again/over time" or "to lock habitually" (e.g., "He always locks the windows before going out.") Usually it is the other signs in the sentence and the context in which it is made that tells you if a sign is to be understood as a noun or a verb.