【单选题】He fell off the bike and ______his leg.
【单选题】He was driving a lorry load of bananas ____he came off the road at a bend and fell into the valley.
【简答题】The boy (take) to hospital at once after he fell off the tree.
【单选题】进行诱变育种时,制备单细胞悬液的要求是 。 1菌体处于对数生长期 2细胞分散且为单细胞(单孢子) 3 菌体处于稳定生长期 4 细菌、放线菌 10 6 个 /ml
【单选题】在高等动物中,脊索和背神经管分别演化为:
【简答题】在诱变育种中为什么要采用应单细胞(或单孢子)?如何制备它们悬浮液?
【单选题】人粪处理不当会给我们人体及环境带来影响,下列哪一项不正确( )
C.
人粪尿可以产生沼气,既净化环境又可作为能源使用
【简答题】He lost his _b__________ and fell off the tree.