题型:填空题 This theory _____ by Einstein. [ ]A. put forward B. had been put forwardC. was put forward D. has put forward 查看答案
题型:填空题 支吊架中的液压阻尼器性能要求包括()。A、液压阻尼器拉撑杆的杆端关节轴承应活动灵活,不应有卡涩现象B、液压阻尼器低速行走阻力不应超过额定荷载的2%C、额定荷载大于50kN的阻尼器,低速行走阻力不应超过其额定荷载的1%D、液压阻尼器实际总位移应不小于标称总行程 查看答案