有两捆粗细相同的铁丝,其中一捆铁丝长8米,重400千克,另一捆铁丝重200千克,这捆铁丝长多少米?
200÷(400÷8),
=200÷50,
=4(米),
答:这捆铁丝长4米.
Tony ____ for the company as an engineer for two decades. Now he teachesmechanics m Peking University.
A.has worked
B.worked
C.is working
D.had worked
Cadherin家族的主要作用是()
A.介导细胞与ECM的黏附
B.介导炎症细胞渗出过程
C.介导免疫细胞的相互识别
D.介导同型细胞间的黏附
E.介导血小板的黏附与聚集