单选题In the US, there is a long waiting list for organs because ______.A there is a shortage of actual organsB only a few people become organ donorsC doctors have set a limit to the number of organ recipientsD transplant surgery is still experimental
题目
单选题
In the US, there is a long waiting list for organs because ______.
A
there is a shortage of actual organs
B
only a few people become organ donors
C
doctors have set a limit to the number of organ recipients
D
transplant surgery is still experimental