v.使 ... 弱，削弱； 变弱； 弄淡

Hansen says if the Gulf stream were to weaken it could affect marine life. 韩森说，如果湾流太弱，会影响海洋生命。

Because transplants weaken the immune system, they cannot be performed on sick patients. 由于移植会使免疫系统变弱，病人在此情况下不能施行手术。

Because transplants weaken the immune system, they cannot be performed on sick patients. 由于移植会使免疫系统变弱，病人在此情况下不能施行手术。

weaken可指生物体表明健康状况的官能效果丧失、体力衰弱,也可指物质或非物质的完整性、稳定性、强度、数量等方面减弱或丧失。引申可指“(使)犹豫”。

weaken既可用作不及物动词,也可用作及物动词。用作及物动词时,接名词或代词作宾语。