Tony is a quiet student, _______ he is active in class. [ ]
A. so
B. and
C. but
D. or
答案:C
下列各组物质中,互为同位素的是
A.C60与C70
B.14C与14N
C.氧气与臭氧
D.6Li与7Li
球结膜水肿见于
A.肝炎
B.颅内高压
C.沙眼
D.高血压不伴颅内高压
E.急性肾小球肾炎