下列烷烃: ①正已烷 ②丙烷 ③正戊烷 ④异戊烷 ⑤癸烷中,沸点由高到低顺序正确的是
A.①②③④⑤
B.⑤①③④②
C.⑤③④①②
D.⑤①④③②
答案:B
There has never been such a beautiful village _________ in the world.
A.anywhere
B.everywhere
C.somewhere
D.nowhere
下列有关剥脱性唇炎的说法不正确的是()
A.该病多见于年轻女性,尤神经质者
B.常伴有脂溢性皮炎、皮脂腺异位症、齿槽脓肿,或有舔唇、咬指甲等习惯
C.多表现为唇红干燥、脱屑或结痂,反复发作
D.多发生于上唇部
E.局部应用皮质激素制剂有效