1 PHRASAL VERB 要求;呼吁;号召 If you call on someone to do something or call upon them to do it, you say publicly that you want them to do it. 要求;呼吁;号召
SYN request, ask, bid, invite
2 PHRASAL VERB (短暂)拜访,探访,看望 If you call on someone or call upon someone, you pay them a short visit. (短暂)拜访,探访,看望