FAQs About the word dropping in (on)

突然拜訪(某人)

致電(至或致),看見,訪問,檢視,尋找(出),順道拜訪

掃一邊(或掃掉),忽視,鄙視,冷落

dropping in => 墜入, dropping by => 順道拜訪, dropping behind => 落後, dropping back => 回滾, dropping (off) => 下降(關閉),