1. Natural killer cell expresses two kinds of recognition receptors with contrary functions:killer cell activatory receptors(KAR) and killer cell inhibitory receptors(KIR). 自然杀伤细胞（NK细胞）可表达两类功能相悖的识别受体，即活化受体（KAR）和抑制受体（KIR）。
2. The effect is obvious on weed control with black film mulched, the fresh weight of weed in field is reduced 70. 利用黑色地膜覆盖防草效果明显，田间杂草鲜重比与黑膜同材质的透明地膜覆盖减少70。
3. In garden, the weed is sparse everywhere. It is not well-marked and doesn't impede the growth of vegetable, flower, and fruit tree, so the gardener doesn't weed with hoe. 园子里的草稀稀疏疏地生在各处，它们不是那么显眼，也不妨碍果蔬，花木的生长，所以园主没有动锄头清理它们。
4. The dodder is one kind of annual autoecious weed of alfalfa, cosmopolitan weed quarantine object. 菟丝子是苜蓿田中最常见的一年生寄生性恶性杂草，是世界性的杂草检疫对象。
5. The dodder is one kind of annual autoecious weed of alfalfa, cosmopolitan weed quarantine object. 菟丝子是苜蓿田中最常见的一年生寄生性恶性杂草，是世界性的杂草检疫对象。
