—How much is the pair of shoes?
-Twenty dollars ______ enough. [ ]
A. is
B. are
C. am
答案:A
用于治疗光化性唇炎
A.口服氯化喹啉 B.放射治疗 C.局部注射皮质激素 D.手术成形 E.湿敷
导致化工及燃料容器,管道补焊事故的原因有哪些?