简述林木良种的基本概念。
参考答案：
多指通过人工选育、性状有一定程度改良的繁殖材料。而良种应是优于当地主栽品种的、新选的品种。
根据下列句子及所给汉语注释，写出空缺处各单词的正确形式。（每空只写一词）
1. A crowd soon collected at the __________(现场) of the accident.
2. The mother ______ (斥责) the boy for not cleaning up his room.
3. Before entering a house in some ______(亚洲) countries, it is good manners to take off your shoes.
4. The animals were left to______(挨饿) to death.
5. He came to miss his homeland when he settled down_____(国外).
6. Please give him my ______(祝贺) when you see him.
7. The shops are in the ______ (中心) position in the city.
8. If today is______(星期三), the day before yesterday was Monday.
9. His father ordered that he keep a ______(日记) in English.
10. Our country has ______ (经历) great changes in the last thirty years.
窑灰钾肥作基肥时，每亩用量为（）kg。
A、50
B、80
C、50～75
D、30
