top something up
phrasal verb with top verb uk/tɒp/ us/tɑːp/ -pp-
(LIQUID)
UK (US top something off)注满，加满（未满的容器）
to add liquid in order to fill to the top a container that is already partly full
Would you like me to top up your drink? 要给你的杯子加满吗？
Mix together some lemon juice and sugar, then top it up with water. 把一些柠檬汁和糖混合起来，然后加满水。
(MONEY)
补足（尤指钱）
to add more of something, especially money, to an existing amount to create the total you need
Students were able to take out loans to top up their grants. 学生能够贷款以弥补助学金的不足。
This is the easiest way to top up your mobile phone. 这是给手机卡充值的最简便办法。
top-up payments 附加款项