下列幼苗发育属于子叶出土型的是(). ["A、棉花","B、小麦","C、玉米","D、豌豆"]
转炉修炉前应做哪些准备工作?
曲线外侧15m高软横跨支柱在垂直线路方向的倾斜率为()。 ["A.0%~0.5%","B.0.5%~1%","C.1%~1.5%","D.1%~2%"]
曲线外侧13m高软横跨支柱在垂直线路方向的倾斜率为()。 ["A.1%~0.3%","B.0%~0.5%","C.0.3%~0.5%","D.0.5%~1%"]
记录技术负责人情况包括:(),(),(),()。
什么叫种子?