leading crop的用法和样例：
例句
- Rice is the chief crop in most southern provinces.
稻子是大多数南方省份的主要作物。 - Triticum aestivum is the second most important crop in China and its production and quality are directly linked with both international and domestic affairs.
小麦是我国第二大主要作物，其产量与品质直接关系到国计民生。
