過去式： ascertained 過去分詞： ascertained 現在分詞： ascertaining
你對啦! ascertain的確是動詞 這句話可以改成 1. We couldn't determine whether... 2. We were unable to ascertain whether... 3. We were unable to ascertain the authorship of the reports...
察言觀色↓ 1.Ascertain intent through word and express 詩情畫意↓ 2.The poetry painting idea...
...the phenotypic monitoring of defined flower genotypes and to ascertain the diffusion and use of transgenic cultivars in the envionment... 其即時檢測...