prolongation/ˌprəulɔŋˈgeɪʃn; ?@ -lɔ:ŋ-; ˌprolɔŋ`ɡeʃən/ n1 [U] prolonging or being prolonged 延长; 延伸.2 [C] addition or extension that prolongs sth 增加或延长的部分.
牛津英汉双解词典