上图是在将plastering, 请问“1. work undercoat well into openings of metal lath to obtain maximum key."和”2.Screed to an even surface and cross scratch each coat to provide a key for the next plaster coat“这两句话分别是什么意思？”key“是指什么？
上图是在将plastering, 请问“1. work undercoat well into openings of metal lath to obtain maximum key."和”2.Screed to an even surface and cross scratch each coat to provide a key for the next plaster coat“这两句话分别是什么意思？”key“是指什么？
