He can't maintain enough equilibrium to ride a bike.他骑自行车不能保持平衡.He can ride a bike now, but he couldn't a few weeks ago.他现在能骑自行车了, 但几星期前他不会.Because I was old enough to ride a bike after I went to junior middle ...
食盐是钠和氯的复合物.Common salt is a compound of sodium and chlorine.它们粘附在抗原 ― ―抗体复合物上.They bind to antigen -- antibody complexes.后一类物质中最有特征性的成份是鼠李糖 - 葡萄糖-IAA糖苷复合物.The best characterized member of this latter group is a rhamnose ...