我国绝大部分位于地球五带中的[ ]
A、北温带
B、北寒带
C、南温带
D、南寒带
答案:A
以下表现可有助于绞窄性肠梗阻诊断的是()
A.腹部阵发性绞痛
B.呕吐出现早而频繁
C.全腹胀
D.肠鸣音亢进
E.腹腔穿刺抽出血性液体
Kevin was not good at Chinese at first. After two months in China, _____, he made great progress.
A.while
B.but
C.however
D.otherwise