A.Have/could have been saved B.Have/could have saved C.Had/could has saved D.Had/could have been saved
A.19世紀(jì)末B.20世紀(jì)末C.20世紀(jì)前半期D.19世紀(jì)前半期
A.混合料中瀝青含量少B.混合料中瀝青含量大C.排水不暢使瀝青膜剝落形成自由瀝青向上遷移D.高溫氣候