下列哪种发电方法对大气有污染(). ["核能发电","风能发电","煤炭发电","水力发电"]
银饰品及材料称量值不大于2000g的,测量允差为()。 ["±0.01g","±0.1g","±0.05g"]
某车总重与货物分配在后桥的载荷分别为2.0吨重及1.8吨重,货物重心近左偏离后桥中心20cm,设两后轮距为2m,则右轮承载力为()吨重。 ["1.5","1.52","1.88","1.9"]
古希腊美术的前兆是(). ["两河流域美术","埃及美术","爱琴美术","迈锡尼美术"]
当车轮相对于车架速度过大时,减振器应自动()液流通道载面。 ["增大","保持","减小","关闭"]
细菌接合(conjugation/mating)