have first call on somethinga) FIRSTto have the right to be the first person to use something 具有使用某物的优先权
b) FIRSTto be the first person that you will help because they are important to you 处于优先〔受助的〕地位 Her children had first call on her time. 她把时间优先用在她的孩子身上。
→ have first call on something at call2(4)