下列各组气候类型，均为欧洲最典型是（   ）

根据短文理解，从A、B、C、D四个选项中选择最佳答案填空。

    One day, a farmer took a bag of wheat to town. He didn't know what 1 when the bag fell off his horse. The bag was 2 heavy for him to lift. He hoped that 3 would come and help him.

    Before long a man came over. But the farmer was 4 when he saw the man, because he was the famous judge(法官) in "town. The farmer was afraid to ask him for 5.

    As soon as he came up to the farmer, the judge 6 his horse and said," You need my help, don't you? Let me help you." Then he took one end of the bag, and the farmer took 7. They 8 the bag of wheat onto the horse.

    "Sir," asked the farmer, "how can I 9 you?"

    "Well," the judge replied, " 10 you see anyone in need of help, do the same for him."

质量为50 kg的乘客乘坐电梯从一层到四层，电梯自一层启动向上做匀加速运动，加速度的大小是1 m/s²，则电梯启动时地板对乘客的支持力为（g取10 m/s²）（   ）

某尿素【CO（NH₂）₂】化肥样品（杂质中不含氮元素）中含氮元素为43%，则此尿素化肥样品的纯度为（　　）